bluuebunny/crossref_metadata_2025 huggingface dataset:
High efficiency laboratory fractionation. I. Gauze ring packing and flooding technique for laboratory columns
Authors: Dison O. C.
Published: July 2007

The development of gauze ring random packing for laboratory scale fractionating columns is described. The packing consists of small open‐ended cylinders of wire gauze and the column is operated in such a manner that a thin film of liquid is maintained over the entire surface of these cylinders. This Aim is produced by flooding the packing before the start of a fractionation and a method of doing this is described. This packing shows a high fractionating efficiency, a fractionating performance of 84 theoretical plates per foot of height having been obtained with some columns. It has also a low hold‐up per theoretical plate and a low pressure drop. It may be used in place of other packings in existing columns.

High efficiency fractionation has been developed in the Billingham laboratories of the Imperial Chemical Industries, Limited, primarily for the analysis of complex hydrocarbon mixtures. Before 1936, the most common random packings were glass and metal beads,1 Lessing rings of metal or ceramic materials,2 metal eyelets, carding teeth,3 and jack chain.4 The fractionating efficiency of these packings was low, being only equivalent to about four theoretical plates per foot of height.

Notable increases in efficiency were later obtained by Fenske5 using single turn wire helices, by Stedman6 who used a regular packing in the form of conical wire gauzes and by Lecky and Ewell7 who produced a spiral packing made from wire gauze.

It was found in these laboratories that the gauze packings of Stedman and Lecky and Ewell were difficult to construct, needed precision bore glass tubing to ensure high efficiency, and that a uniform flow of reflux over the gauze surface was not obtainable. To improve the liquid distribution copper gauze cylinders in the form of Lessing rings 1/8 in. × 1/8 in. were introduced into the empty spaces around the cones of the Stedman packing and a great improvement in efficiency was obtained. A further improvement was obtained by removing the gauze cones completely and replacing them with more gauze rings. Since this cylindrical packing was comparatively easy to manufacture and use, the development work on other packings was abandoned and from 1941 to 1943 a study was made of the variables affecting the performance of this packing. The results of this work are summarized in this paper. A mixture of 20% normal heptane and 80% methyl cyclohexane was used throughout for the determination of fractionating efficiency.
A “Tablet” method for the determination of dissolved oxygen in de‐aerated water
Authors: Killner Wycliffe
Published: July 2007

The part played by oxygen dissolved in feed water in the corrosion of marine boilers has long been known, and de‐aerating plants to eliminate or reduce the oxygen content have been installed wherever a closed feed system exists. This method is designed to enable the determination of dissolved oxygen to be carried out by ships' personnel, so that a check can be kept on the de‐aerating plant and closed feed system.
An improved technique for measurement of the dispersing powers of detergents
Authors: Snell Foster D. , Reich Irving
Published: July 2007

Effective detergent action requires that soil be detached from the fabric. The usual technique with detergents is then to de‐flocculate and suspend in the detergent solution so that it can be rinsed away without re‐deposition. Experience shows that lack of sufficient dispersing power is the most common reason for poor detergent performance.

A method for measuring dispersing power previously described has been made simpler and less time‐consuming. The present method calls for agitating a lightly‐oiled umber soil with detergent solution, permitting to stand in a Nessler tube for two hours, then pipetting off a sample of the suspension and determining its turbidity in a modified electric turbidimeter. The results are best expressed directly as 100 times the reciprocal of the length needed to just obscure the filament. The variation of reciprocal value with concentration of suspended soil is shown to be linear.

When the detergent solution is cloudy, a correction is applied by subtracting the reciprocal reading of the detergent solution from the reciprocal reading of the suspension, thus obtaining a corrected reciprocal reading.

Typical dispersing power values for various types of detergents are listed. Soaps yield Values considerably higher than most synthetic agents.
Application of fumigants to ships and warehouses. VI. Fumigation of dried fruit with methyl bromide in chambers
Authors: Page A. B. P. , Lubatti O. F. , Russell John
Published: July 2007

These experiments are the first of a series designed to provide safe and efficient fumigation of dried fruit with methyl bromide. Bituminous felt chambers can be used with safety if they are well made and kept in good condition, but loss of methyl bromide exceeds the unavoidable loss by sorption in the fruit and wooden. boxes. With the usual open stacking, distribution and penetration arc satisfactory and only slight improvement is produced by Slow circulation. In these experiments airing for two hours was sufficient to permit unloading. Residues in fruit are extremely small.
α‐monostearin and sodium stearate as emulsifying agents
Authors: Jellinek H. H. G. , Anson H. A.
Published: July 2007

I. Interfacial tensions of the following systems have been measured at 70°C. by a capillary height method:

(a) Water‐white oil containing α‐monostearin against water; (b) Water‐white oil against water containing sodium stearate; (c) Water‐white oil containing α‐monostearin against water containing sodium stearate.

The areas (in Angstrom units) occupied by each molecule at the interface have been evaluated from the interfacial data obtained.

2. Separation of phases at 70° of emulsions of Water‐white oil and water containing cither α‐monostearin in the oil or sodium stearate in wafer or both emulsifying agents, has been studied under controlled conditions. The phase volume ratio has been kept constant at I : I in all experiments.

3. It was ascertained that α‐monostearin gives W/O emulsions, but that the addition of sodium stearate to the water phase leads to the formation of O/W emulsions. The amount of sodium stearate needed to bring about the inversion is only slightly dependent on the concentrations of e‐monostearin in the range of concentrations investigated. A combination of both emulsifying agents gives more stable emulsions than equivalent amounts of each emulsifying agent alone. The mechanism of inversion is discussed. The appearance of the emulsions has been characterised microscopically.
Prevention of gas explosions in chemical manufacturing plants
Authors: Jones Elwyn
Published: July 2007

The normal method of eliminating the danger of explosion with mixtures of an inflammable gas and air or oxygen is to render the mixture incapable of flame propagation either by using a large excess of one component or by the addition of an inert diluent. Consideration of the limits of inflammability of mixed gases suggests another and more powerful method, namely, the introduction of an additional inflammable ingredient of a type which has a low upper limit of flame propagation. The hit concentration being measured by volume, suitable additives will normally be characterized by a high molecular weight. A wide choice of such materials is available so that a suitable additive can probably be found to satisfy any specific requirement.
High efficiency laboratory fractionation. II. Glass laboratory stills
Authors: Dixon O. G.
Published: July 2007

Two glass fractionating columns for precise laboratory work are described. They have boilers of capacity 200 ml. and 1 litre respectively. Both are capable of fractionating material of boiling point up to 300° c. at atmospheric or reduced pressure.

The boiler and column in each case are surrounded by oil jackets which prevent heat losses from the system. Boilers and jackets are electrically heated.

Gauze ring packing, fully described in a previous paper,1 is used together with a device which enables the packing to be flooded and it is to these features that the high efficiency of the fractionating columns is ascribed.

In a previous paper1 the development and use of gauze ring packing for high efficiency fractionation was described and the importance of proper preflooding was emphasized. This paper describes fractionating apparatus which is easily controlled, in which the operating conditions have been determined, and where gauze ring packing may be used to its full advantage.
Wurtz‐fittig reactions involving silicon tetrachloride
Authors: Ridge D. , Todd M.
Published: July 2007

Reactions have been carried out using chloro‐2 : 4‐dinitrobmzme, m‐chloronitrobenzene and p‐chloranisole as the organic halide. Negative results were obtained.
Organoleptic tests in the food industry. III.‐Some statistical considerations in organoleptic tests
Authors: Wood Eric C.
Published: July 2007

The principles underlying the correct interpretation of the judgments of Tasting Panels are discussed with special reference to the use of an analysis of variance. Certain assumptions inherent in present methods for assigning palatability scores are examined critically. There is some risk of erroneous conclusions when a series of scores, each for one desirable quality, is to be combined to obtain a single score for general palatability; suggestions arc made for improving the correlation between such scores and consumers' actual verdicts.
A modified vapour‐liouid equilibrium still
Authors: Fowler R. T.
Published: July 2007

For many years the equilibrium still proposed by Othmer in 1928,1 and its modifications by Carey and Lewis,2 Trimble and Pott,3 Langdon and Keyes4 and others have been widely used and sad to give good results. Other workers, viz., Jones, Schoenborn yd Colburn,5 Scatchard, Raymond and. Gilman6 have reported variations, in the results previously obtained, and proposed designs of varying complexity. It is therefore a matter of some difficulty to decide which results should be accepted.
The auto‐siphon meter. A device for the precise measurement of liquid flow
Authors: Miles F. D. , Smith David
Published: July 2007

The auto‐siphon meter is essentially an automatic pipette which receives a continuous flow of liquid and delivers it into a pipe or tank below, in successive discharges which are constant in volume to at least 1 in 500, at any overall rate in a considerable range. The number of discharges is recorded by a counter. The meter was developed to give an accurate estimation of the production of nitric acid or sulphuric acid plants, but can be used for the measurement of any mobile liquid. The usual method of “dipping” with graduated rods in calibrated storage tanks is sound in principle, but has many practical disadvantages and long experience has shown that to determine accurately the amount of a production or of n supply of liquid acid, some better means than this must be found.
A thermostatically‐controlled micro‐polarimeter tube
Authors: Kacser H. , Ubbelohde A. R.
Published: July 2007

A discussion is given of the design of tubes for precision micropolarimetry, which involves the consideration of sources of error negligible in ordinary tubes. A micro‐tube has been developed which is adapted to the conventional polarizer and analyser. Special provision has been made for easy filling and recovery of solution, accurate temperature control, and rapid temperature changes. The design minimizes errors due to optical and manipulative causes. Comparison with other polarimeters described in the literature shows that the precision is equal to that of good macro‐tubes and better than most micro‐tubes. The range of conditions over which Useful data can be obtained is substantially wider than with previously described micro‐tubes.
Practical experience in silica‐assisted coagulation of polluted surface water
Authors: Sherratt J. Graham
Published: July 2007

Some methods for the preparation and use of “Activated Silica” as an aid to aluminium sulphate in the coagulation of polluted waters arc described. It is shown that transfer from laboratory tests to full scale plant operation involves certain modifications for the successful use of activated silica. Suitable ratios of silica to aluminium sulphate are mentioned, and general methods of operating the process arc discussed. Reference is briefly made to relative running costs, and to some advantages that may be derived from the application of this system.
New methods for the routine gravimetric analysis of boiler scales and deposits containing phosphate
Authors: Edwards J. E. , Alcock C. P.
Published: July 2007

Methods are described for the gravimetric determination of Calcium, Iron, Aluminium and Magnesium in the presence of Phosphate, without the removal of the phosphate.
The rapid determination of free acid and water‐soluble phosphate in calcium superphosphate
Authors: Guthrie F. C. , Nance J. T.
Published: July 2007

The sample of superphosphate is extracted with water, and the solution titrated with carbonate‐free sodium hydroxide in two stages with appropriate indicators. The first stage gives the free acid, and the second stage an approximate result for the primary calcium phosphate, Ca(H2PO4)2. A suitable volume of the sodium hydroxide is then titrated with the superphosphate solution, giving a reading from which a more accurate value for the primary calcium phosphate can be obtained. The total soluble phosphate determined in this way agrees well with that found by gravimetric analysis.
The analysis of mixtures of the stereoisomerides of hexachloro‐cyclohexane (benzene hexachloride) by means of infra‐red spectro‐scopy
Authors: Marrison L. W.
Published: July 2007

A description is given of the rapid analysis of mixtures of the stereoisomers of hexachlorocyclohexane by means of infrared spectroscopy. The results obtained arc within 0·5 to 2·5% of the correct values. More than 100 samples per week can be analysed.
Reactive methylene groups. Part I. Stilbene formation
Authors: McGookin A.
Published: July 2007

The Ehrlich‐Sachs reaction' consists in condensing a compound containing a reactive aethylenc group, c.g., 2 : 4‐dinitrotoluene, with an aromatic nitroso‐compound, Substituted aldehydcs and ketones may. then b' prepared from the resulting azomethines by hydrolysis With plinerol. acid. Since the yields of final product were ofren mausfactory 11 appeared possible to achieve thc same end by condensing the rcacuve methylene compound with an aromatic aldehyde, e.g. and oxidizing, or ozonizing, the resulting stilbcnc to the required aldehyde.

The polynitrostilbenes, however, proved to be highly resistant to oxidation and the strenuous conditions required to achieve success resulted in the formation of the corresponding acid. Ozonolysis, likewise, furnished chiefly the acid, although small quantities of aldehyde were isolable (compare Kaslow and Stayner'). Since the hydrogen peroxide formed during the decomposition of the ozonide might be responsible for the oxidation of the aldehyde to thc acid, reducing gcnts such as aqueous fcrrous sulphatc were used to dccomposc the ozonidc, but :he main product was still the acid. From this result it seems probable that there is a peroxide present which inevitably produces the acid on hydrolysis.

The work instigated an investigation into the reactivity of methylene groups in general, the results of which will be published later. A number of improvements in stilbene production are recorded. Thus the yield of 2 : 4‐dinitrostilbene was maintained by using toluene as a solvent and the product was much more 'readily purified than that obtained without a solvent. The crude yields of stilbcnes frequently quoted in the literature arc of little value, since tlic final yield of pure matcrial is often considerably lower. For instance, in the preparation of 2 : 4‐dinitrostilbcnc, Thiele and Escalcs' crude yield of 90‐95 is attainable, but the final yield of pure product amounts to about 759 the rcmaindcr being an intracrablc tar.

Benzoyl p‐hydroxybenwldchyde and z: 4‐dinitro‐bcnzoyloxy‐stilbenc do not appear 10 have bcen described previously.
The properties of some higher polymethacrylic esters
Authors: Crawford J. W. C.
Published: July 2007

Although the properties of polymethyl methncrylate have been widely reported in the scientific and technical literature, few1 references appear to studies of the properties of the higher‐polyalkyl methacrylates.

The present paper deals with examination or re‐examination of a number of polymeric higher methacrylic esters undertaken with a view to obtaining information on the influence of thee alcohol alkyl chain length, and of branching in this chain on the properties of the polymer.

Polymers have been examined of all the alkyl methacrylates up to the butyl series. Of the amyl hexyl and octyl series a selection has been prepared out of the many possible isomers, the choice having been indicated by the results of work on the lower homologues.

Attempts have been made to explain differences in the properties of the polymers mainly on the basis of induction due to methyl groups in the alcohol alkyl radicals. This would be only one of numerous causes of differences in properties, but the assumption that it is important has led to results which appear to be of sufficient interest to discuss in the present paper.
A simple fraction‐collecting machine for chromatographic analysis
Authors: Cuckow F. W. , Harris H. J. C. , Speed F. E.
Published: July 2007

The machine has been designed for work on the partition chromatography of amino acids and of purine and pyrimidine nucleosides to facilitate the collection of successive fractions of small volumes of the percolate from the chromatographic column. Each fraction (of up to 50 ml.) is collected for a pre‐determined time and sixty such fractions in all may be obtained without resetting the machine.
Studies in acetylene flames. Part I. Extinction
Authors: Campbell J. R. , Cumminc A. P. C. , Horn J. A.
Published: July 2007

The extinction point of acetylene was determined by burning a vertical he under constant pressure and in an atmosphere consisting of O2 and N2 of constant composition which could be altered at will. The length of flame, the diameter of the combustion chamber, the velocity of the gas mixture through the combustion chamber, and the percentage excess air all affect the extinction point. The results under specific conditions are given in the conclusions. The presence of CO2 in the inlet gas mixture increases the value of the extinction point but to a lesser extent then that previously found for other hydrocarbon gases, e.g., methane.
An introduction to the micro‐oven technique as applied to bakery research
Authors: Bradshaw R. C. A. , Coppock J. B. M.
Published: July 2007

A new technique is described for studying the changes that take place in doughs, batters etc. using a micro‐oven. The problems associated with its use are reviewed, and illustrations are given showing its application 10 bread doughs, sponge mixtures and emulsions.
The preparation of polysulphide, polymers from crude 2:2′‐dichloro‐diethyl sulphide
Authors: Abrams J. T. , Barker R. L. , Jones W. E. , Woodward F. N.
Published: July 2007

Thiokol‐type polymers have been prepared by condensation of crude 2: 2′‐dichlorodicthyl sulphide with sodium polysulphides. More useful products are obtained by replacing part of the 2 : 2′‐dichlorodicthyl sulphide by the corresponding sulphoxide and condensation of the latter with ethylene dichloride under similar conditions also gives useful polymers.

The work described is mainly based on the use of sodium tetrasulphide condensates but concurrently and in conjunction, similar work mainly based on the use of sodium disulphide condensates was carried out by the Paint Research Station with the view to producing more resinous than rubber‐like polymers. The outcome of the work of the Paint Research Station is detailed in British Patents Nos. 573,308,573,333 and 576,721 (Jordan and Aiken) which also cover the use of the sulphoxide compound.
The degradation of vinyl polymers
Authors: Reid W. S.
Published: July 2007

The degradation of a high polymer is the process of breakdown by various agencies of the long chain molecules. In the case of vinyl polymers, (the degradation reaction, though not so important commercially as the polymerization process,) may be utilized in various ways; for instance, (a) polymers such as rubber may be more easily processed if first degraded and the degree of polymerization stabilized at some lower level.

(b) monomer may be regenerated from scrap polymer, (c) compounds which cannot easily be synthesized can be produced by chemical reaction with the polymer and subsequent depolymerization, (d) the process may elucidate polymer structure.

The degradation of three representative polymers, namely, those of styrene, methyl methacrylate and x‐methylstyrene, (I, II, III), is discussed here Low polymers of α‐methylstyrene have a cyclic structure, but longer chains may contain branches due to activation of the methyl group.

In general, degradation increases with reaction temperature, and structures containing quaternary carbon (or hetero) atoms are most readily and perfectly degraded. The destructive distillation polymethyl methncrylate and poly α‐methylstyrene yields more than 90% monomer, but only 60‐65% is obtained from polystyrene.

Degradation, whether in bulk pyrolytic or in solution, exhibits the same fundamental principles.
Degradation of vinylidene chloride co‐polymers in solution
Authors: Jackson D. L. C.
Published: July 2007

It has been shown1 that most degradation processes in vinyl polymers can be regarded as polymerization processes in reverse, both occurring by means of a radical mechanism. Under certain experimental conditions, both aggregative and disaggragative processes can proceed simultaneously.

The experiments to be described constitute a specific example of the degradation by a radical mechanism of a vinyl halide co‐polymer in solution.2 Dilute solutions of the co‐polymer were used, and the experimental conditions are such that the aggregative reactions are suppressed, while the disaggregative or degradation reactions arc accentuated.

The experiments arose from an observation made in the course of some work involving solutions of a vinylidene chloride co‐polymer, when it was found that solutions of the co‐polymer in tetrahydro‐furan showed a reduction in viscosity when aged at temperatures about 50° c., or above.
Electronic effects in certain chemical reactions
Authors: McGowan J. C.
Published: July 2007

It has been shown that certain relationships exist between ionization constants. In the light of these relationships the influence of inductive effects upon velocity constants of chemical reactions has been considered. Regularities have been found for reactions involving the side chain of phenyl compounds with meta or pan constituents and indications are given of the Structure of complexes formed as intermediates. The study of inductive effects in a series of biologically active compounds may give some indication of the mode of action: for example, the toxic action of certain phenols towards some micro‐organisms seems to depend upon the formation of hydrogen bonds.
The cuprous chloride catalysed condensation of arsenious chloride with acetylene
Authors: Heweit C. L. , Jones W. E. , Vallender H. W. , Woodward F. N.
Published: July 2007

Lewisite I, containing a small proportion of Lewisite II, is readily obtained in good yield by passing acetylene into a vigorously stirred mixture of arsenious chloride in carbon tetrachloride and a concentrated solution of cuprous chloride in aqueous ethanolamine hydrochloride. The reaction is most conveniently carried out continuously.
the analysis of crude lewisite
Authors: Jones W. E. , Vallender H. W. , Woodward F. N.
Published: July 2007

Two methods have been evolved for the analysis of crude lewisite and the determination of lewisite I by the acetylene evolution method has also been investigated. Conditions have also been worked out for the estimation of arsenious chloride in crude lewisite by a gravimetric method.
Corrosion inhibitive action of zinc compounds
Authors: Mayne J. E. O.
Published: July 2007

Lewis and Evans1 examined the corrosion of steel produced by drops of 0.001 M sodium chloride solution applied to a film of paint, which had been interrupted by the engraving of a standard scratch line. They found that zinc dust, zinc oxide and a number of lead compounds prevented corrosion at the scratch line. The role of lead compounds has been examined by the author,2 and it has been established that inhibition is associated with the formation of lead soaps. In the case of zinc dust it has been shown3 that when the zinc dust content of the paint film is sufficiently high, the steel may be protected cathodically. Zinc oxide cannot function in this manner, nor can zinc dust do SO when the paint film contains less than a certain amount.

The following investigation has been carried our in order to establish the way in which various zinc pigments inhibit corrosion.
Some aspects of the use of mineral oils in baking practice with particular reference to bread
Authors: Coppock J. B. M. , Cookson M. A.
Published: July 2007

Mineral oil used for lubricating or greasing purposes by the Baking Industry is absorbed to some degree by the baked product. An analytical method is described for the determination of mineral oils in bread, and the way by which such oils are bound in the bread is discussed. The possible physiological effect of oils so used is considered, as a result of which it has been suggested that bread should not contain mineral oil of chemical purity less than that of Liquid Paraffin B.P., nor should the quantity of oil exceed 0.2%.
The continuous preparation of diphenylchloroarsine
Authors: Barker R. L. , Booth E. , Jones W. E. , Millidge A. F. , Woodward F. N.
Published: July 2007

Phenylarsonic acid in hydrochloric acid is readily reduced continuously to phenyldichloroarsine with sulphur dioxide, and an all‐glass apparatus was designed for the production of 30 lb. per hour. This material was then partially hydrolysed continuously by water to a 50/50 mixture of phenyldichloroarsine and phenylarsenoxide which after drying, was continuously at 290‐300° c. in a mild steel apparatus. This stage did not proceed very satisfactorily except at the beginning of the experiments, owns to corrosion of the metal which led to the deposition of a gelatinous form of arsenious oxide stable only above a temperature in the region of 200°C.
The catalysed condensation of phenyldichloroarsine with pheny‐larsenoxide
Authors: Barker R. L. , Booth E. , Jones W. E. , Woodward F. N.
Published: July 2007

Thc reaction between phenyldichloroarsinc and phcnylarsenoxide to give arsenious oxide and diphenylchloroarsine has .been found to be catalysed by a number of materials, notably iron, ferric chloride, zinc chloride and zinc oxide. The last is both the most convenient and most active, and in glass 0.1%, permitted a reduction of the reaction temperature from 240°c. to 200°c. and the time from 4‐2 hours compared with that of the uncatalysed condensation of 50/50 mixtures, In mild steel reactors with 0.1% of zinc oxide the temperature could be reduced to 140°c. and under these conditions it was possible to use the stoichiometric ratio of reactants.
Moisture relationships of palm kernels, jute and jute contaminated with palm kernel fat
Authors: Burcoyne J. H. , Thomas A.
Published: July 2007

The prolonged exposure of palm kernels to 81% R.H. and above at 25°c. IS conducive to mould growth. A satisfactory steriliention technique involving the use of methyl bromide was developed and shown to be without prejudice to determination8 of relative humidity‐moisture regain‐ relationships.

Hygroscopic equilibria between the gas and solid phases were measured at 25°c. over the range 0 to 100% R. H. (with particular reference to the range 50% to 100%) for samples of paln kernels, of jute sacking contaminated with palm kernel fat, and of uncontaminated sacking of a similar type. The sterilisation procedure was utilised at and above 81% R. H.
Partially chlorinated derivatives of rubber
Authors: Woods D. E.
Published: July 2007

Chlorinated rubbers containing from 1 to 17% of chlorine have been prepared by direct chlorination, at ordinary temperature, of crèpe rubber dissolved in carbon tetrachloride. It has been found that these products retain, to a greater or lesser degree, rubber‐like properties and are capable of hot or cold vulcanization with or without the addition of vulcanizing agents. The resulting vulcanizates have been shown to be considerably more resistant to the swelling action of solvents, and also to the action of chlorine, than corresponding products prepared from crèpe rubber. The resistance to swelling agents increased with increase of combined chlorine content; tensile strength and elasticity, however, decreased with increasing chlorine content. As expected, hardness increased with increase of chlorine content and vulcanizates from derivatives containing more than 10% combined chlorine were not sufficiently rubber‐like to warrant many experiments. It was found that fully Chlorinated rubber was compatible with partially chlorinated rubber and addition of the former was necessary for vulcanizates to pass the Post Office flame test for cables.
Hydroextraction. Part I. The flow relationships in a basket centrifuge
Authors: Burak N. , Storrow J. Anderson
Published: July 2007

The flow of water through starch held in a perforated basket centrifuge has been related to the dimensions of the system by equating the centrifugal driving force on the liquid to the frictional resistance to flow through the cake. The analysis has been tested by using “critical wetting” conditions with the liquid surface coinciding with the inner surface of the cake. Values of the permeability in the centrifuge differ greatly from those found in normal filtration zests on samples cut from the centrifuge cakes. The possible explanations of this difference have been discussed.
African drying oils. II. Component acids of some linoleic‐rich oils. Niger seed oil
Authors: Dunn H. C. , Hilditch T. P.
Published: July 2007

Parts II, III and IV of this series deal with the component acids of Niger seed, safflower and sunflower seed oils from different parts of Africa. The linoleic acid content of such oils may range from over 70% to somewhat below 50%; the oils of high linoleic acid content possess excellent drying properties, coupled with absence of yellowing during ageing of the resulting paint film.

In this paper the component acids of the oil of Niger seed grown in Southern Rhodesia have been studied and found to contain about 73% of linoleic acid and 1%, of linolenic acid, with 7% of oleic and about 19%, a of saturated (palmitic and stearic) acids. So far as the present (somewhat meagre) records go, it appears that African Niger seed oils may usually approximate to this composition, whereas Niger seed grown in India yields oils with only about 50% (or slightly more) of linoleic acid.
An investigation of the possibility of the occurrence of phosphine and acetylene in the atmosphere of factories for the powdering of magnesium
Authors: Cole R. J. , Bensett W. H.
Published: July 2007

The hydrogen evolved when magnesium billet (arsenic‐free, but found to contain phosphorus) is dissolved in dilute acid contains phosphine, but no acetylene, as also docs the air in the immediate vicinity of magnesium powder during manufacture of the latter from bulk metal.
The stability of carotene solutions towards oxidation
Authors: McGillivray W. A.
Published: July 2007

The rates of decomposition of carotene in liquid paraffin and in hydrogenated coconut oil under accelerated conditions at 100° C. with forced aeration have been investigated. In the case of paraffin containing less than 50μg./ml., the rate is shown to be proportional to the log. of the concentration. The spectral changes occurring during oxidation at 100° c. and irradiation at room temperature hare also been followed and it is shown that the estimation of vitamin A in the presence of oxidized carotene by direct spectroscopic measurement is possible provided a simple correction is applied. Hydrogenated Coconut oil is suggested as a suitable solvent for carotene in feeding trial work.
Surface dressing machinery
Authors: Waters D. B. , Russell W. L.
Published: July 2007

The paper deals with the machinery required for modern surface‐dressing work. For convenience the subject is divided as follows:

Binder distributors

Gritting and loading machinery

Rollers

The principles involved in the design and operation of the common types of binder distributor are discussed, and photographs arc shown of representative machines. Common faults occurring in the work done by the different distributors arc considered. Tests are described for measuring transverse and longitudinal uniformity of binder film, and results are quoted to show the quality of some of the work being done at the present time; practical tolerances are suggested.

Several types of gritting machine arc described and the results given of an investigation made on 12 sites to compare the number of men used and the output obtained from four types of primer. A single result is given to show how fast a normal gang can spread chippings if not held up for materials. Some measurements have also been made on the transverse and longitudinal variation in the rate of spread of chippings by the different methods. Brief descriptions are given of three modern methods of loading chippings (self‐loading elevator, the mechanical shovel and the clam‐shell grab) and some figures are given for the output of each. The size of roller required for finishing the dressing is discussed and an experiment is described in which sections have been laid with different weights of roller and without any roller at all.
Some colour reactions of phloroglucinol
Authors: Ismay Doreen
Published: July 2007

Phloroglucinol in the presence of hydrochloric acid gives a red colour with certain aldehydes, lignified tissue, the mould product viridin and oxidized hydroquinone; it is also said to give a red dour with compounds containing allyl groups. These reactions have been investigated. A number of aldehydes and oxidized hydroquhones give the reaction but pure allyl compounds do not. The aldehydes and hydroquinones may be distinguished by the use of phloroglucinol derivatives in place of phloroglucinol itself.
African drying oils. V. Some nigerian and sudanese drying oils
Authors: Barker C. , Dunn H. C. , Hilditch T. P.
Published: July 2007

The fatty oils from the seeds of Hyptis spicigera and Ocimum viride from Nigeria, and of O. kilimandscharicum, Euphorbia calycina, E. erythracac, and Charozophora plicata from the Sudan, have been examined with reference to their component fatty acids and their suitability as drying oils. The oils of H. spicigera, O. kilimandscharicum and Euphorbia calycina closely resemble conophor oil in their fatty acids and their high content of linolenic acid; that of E. erythracae is very similar to linseed oil in composition, and C. plicata seed oil resembles cottonseed oil in its proportions of linolcic, oleic and saturated acids, Features in the distribution, cultivation, or harvesting of the seeds under discussion would appear to present certain difficulties in their commercial exploitation as compared with Tetracarpidium (conophor), but it is clear seeds which yield oils equal or superior to linseed oil in drying properties, as indicated by their respective contents of linolenic glycerides.
The determination of small amounts of sulphur in organic compounds
Authors: Wilson H. N. , Straw H. T.
Published: July 2007

A recently described apparatus for the determination of traces of sulphur in organic compounds has been investigated. The original method described B vertical tube heated to 830° C. and packed with silica, on to which the sample was allowed to fall drop by drop, and burnt in a rapid current of air. The silica packing was quite unsatisfactory, but by substitution of an oxidation catalyst such as vanadium pentoxide on alumina, very satisfactory results me obtained, The apparatus requires little skilled attention, is rapid, and un be applied to a very wide variety of substances ranging in volatility from petrol to sperm oil.
Studies in the coal tar bases. II. The isolation of 2‐methyl‐6ethylpyridine from a lutidine fraction
Authors: Jones J. Idris
Published: July 2007

2‐Mcthyl‐6‐cthylpyridinc, hitherto not reported as a coal tar constituent, has been isolated from a lutidine fraction of coal tar bases as an zoetrope with proionic acid. Its orientation has been established by oxidation to picolinic acid and by comparison of its ultraviolet absorption spectrum with that of 2 : 6‐lutidine.
Detection of abietic acid in bituminous coal
Authors: Golumbic C. , Hofer L. J. E. , Peebles W. C. , Orchin M.
Published: July 2007

Dispersions of a bituminous coal in phenanthrene were examined by X‐ray powder photography. A characteristic diffraction pattern was observed which was found to be identical with that given by partly amorphous abietic acid and aluminium and ferric abictates. No reliable estimate of the concentrations of these constituents could be made, but qualitative observations indicated that they arc minor constituents.
The esters of 4‐hydroxybenzoic acid and related compounds. IV. The bacteriostatic action of n‐alkyl 4‐hydroxybenzoates
Authors: Murrell W. G. , Vincent J. M.
Published: July 2007

Detailed growth curves based on progressive turbidity readings have been used to study the inhibition of Aerobacter aerogenes Type I, by a series of alkyl 4‐hydroxybentoates. Results in the lag phase are irregular, but it is apparent that the elongation of this phase becomes very marked at the higher concentrations of the inhibitor and that complete inhibition of growth occurs at a concentration that extends lag indefinitely rather than at one which reduces the growth rate to zero. Inhibition in the logarithmic phase, plotted as a function of inhibitor concentration, gives curves convex to the abscissa that contrast with experience of fungi, where characteristic concave adsorption forms have been obtained. However, the convexity of the present series of curves is likely to be a reflection of secondary effects associated with this method of determining bacterial inhibition, particularly in that there is a loss of viability in cells exposed to the higher concentrations. Determinations based on stationary populations arc convenient and give good agreement between experiments, but are not necessarily related in any simple fashion to growth rate inhibition.

Although the order of increasing activity with increasing chain length of the esters is similar that found for fungi the activity of the methyl ester is less against Aerobacter aerogenes so that solubility difficulties soon prevent the attainment of a reasonable level of inhibition.

Growth curve methods that use a relatively small inoculum with consequent lag phase of variable length do not appear well suited for a direct study of growth rate inhibition.

Growth curve method that use a relatively small inoculum with consequent lag phase of variable length do not appear well suited for a direct study of growth rate inhibition. A simple method better suited to this purpose is being developed.
Catalytic oxidation of mono‐ethenoid fatty acids; The catalytic influence of cations of metals of the typical and transitional series in autoxidation processes
Authors: Skellon J. H.
Published: July 2007

The influence of metal cations of the typical and transitional series in catalytic oxidation of oleic acid has been investigated over a wide range of conditions. The results of a series of oxidations, in which the catalyst metal ion content was adjusted to a constant value, have afforded new information concerning the intrinsic effect of metal ions on oxygen absorption by mono‐ethenoid acids.

A new relative order of efficiency of metal cation catalysts in autoxidation processes has been obtained. The catalytic activity of the metal ions is correlated with their atomic structure and is shown to be a periodic function. A theory of catalytic activity is advanced applicable to metals used for promoting gaseous oxidation of unsaturated fatty acids and esters, and for the oxidation of parent oils.
Some reactions of cerium and other rare earths with chlorine and hypochlorite
Authors: Vickery R. C.
Published: July 2007

Previous work on the influence of basicity on the oxidation, hydrolysis of cerium salts included a preliminary study of its reaction with OCl‐ ions.1 The results then obtained have now been more fully examined and the work extended to yield the data here recorded.

It is shown that compounds of the type RCl3, R(OCl)3 can be prepared by interaction of Cl2 and HOCl with the rare earth hydroxides and that these compounds exhibit the reactions Of hypochlorites. In the presence of water these compounds are unstable and their transitory formation is considered to be a fundamental reaction in Mosander's chlorination process and the ‘basic chloride’ process for the separation and purification of cerium.
The colorimetric bromothymol blue method for determining small quantities of nicotine
Authors: Rinthakul C. , Hannen J.
Published: July 2007

A rapid and accurate method for determination of nicotine in a large number of plant or dust samples is described. Nicotine is extracted with light petroleum from an alkaline suspension of finely powdered material. The petroleum is then shaken with dilute hydrochloric acid and the aqueous portion is made up to volume. An aliquot is treated with 0·04% bromothymol blue and a suitable buffer, and shaken with chloroform; the nicotine is determined by examination of the coloured chloroform extract in a Spekker absorptiometer, using a 601 violet filter.
Absorption of hydrogen sulphide by peat in the presence of ammonia
Authors: Campbell J. H. , Skilling W. J.
Published: July 2007

The influence of the following factors on the efficiency of peat in removing hydrogen sulphide from mixtures of it with air, oxygen or nitrogen and 3 little ammonia has been investigated: (a) variation of ammonia supplied, (b) variation of oxygen content of gas, (c) variation of moisture content of peat, (d) variation of weight of peat, (e) variation of diameter of reaction tube, (f) dilution of peat with sawdust (g) sterilization of pent, and (h) depth of source of peat.

In addition, the activities of other absorbents and of humic acids from peat have been examined, and figures for the saturation of peat with sulphur have been obtained; finally, the activity of peat and humic acids saturated with ammonia has been ascertained. A hypothesis has been submitted to explain the experimental evidence: this suggests that the reaction is based on combination of ammonia with the humic acids in pear, followed by the decomposition of the ammonium humates with hydrogen sulphide. The resulting ammonium hydrogen sulphide is then oxidized to ammonia and free sulphur, and the regenerated ammonia is available for further reaction.
The electrostatic ignitibility of dust clouds and powders
Authors: Boyle A. R. , Llewellyn F. J.
Published: July 2007

The electrostatic ignitibilities of a number of varied substances in the form of dust clouds or powders have been determined under a variety of conditions; the work is divided into three pans. Results for dust clouds of magnesium, aluminium, ferro‐manganese, zinc and silicon are given; under certain circumstances granular aluminium presents an electrostatic hazard of the same magnitude as magnesium. The minimum condenser energies required for the ignition of dust clouds of tetryl, acaroid resin, polymethyl methacrylate. sugar and flowers of sulphur are 0·012, 0·017, 0·5, 0·009 joules respectively; the effect on these ignitibilities of including a resistance in the discharge circuit aid of varying the size of the capacity is discussed. The electrostatic ignitibilities of guncotton and cordite in the dry state are 0·012 and 0·10 joules respectively. The effect of moisture content on the ignitibility of guncotton and the effect of panicle size, nitrogen content, and the size of the discharging capacity on the ignitibilities of nitrocellulose, guncotton and cordite is discussed.
Analysis of methylamines, with special reference to the products from ammonium salts and aqueous formaldehyde
Authors: Attwood C. W. , Ford I. A. M. , Hoyle E. R. , Parkes D. W.
Published: July 2007

Methods have been developed which allow of full analysis of the known basic products formed in the reaction between aqueous ammonium salts and formaldehyde, namely of ammonia, mono‐, di‐, and trimethylamines, and the condensation products of formaldehyde with mono‐ and dimethylamines. The methods have advantages Were those already proposed in that concentration of the solution of salts, which leads to changes in composition, is avoided.

A method is also described for the approximate determination of the formic acid content of the reaction product.
Reactive methylene groups. II. Stilbene formation in solvents
Authors: Hargreaves K. R. , McGookin A.
Published: July 2007

As a means of comparing the reactivities of methylene groups in organic compounds& substances have been condensed, under comparable conditions, with aromatic aldehydes in solution in organic solvents. Benzene is the most satisfactory solvent.
Fabric‐base plastics. II. Interlaminar strength
Authors: Pepper K. W. , Riddell J. R.
Published: July 2007

The strength of laminated plastics derives mainly from the fibrous reinforcement, but the fibres, being arranged in layers, cannot contribute to the interlaminar strength. The consequent weakness is revealed by a low cross‐tensile strength and a low shear strength parallel to the laminations. Three methods of test which have been used pith laminates ¼ in thick are described and compared with material greater than ¼ in. in thickness, two additional tests may be employed.

Certain variables in the preparation of phenolic‐bonded laminates are shown not to be critical, but interlaminar of strength in common with other properties of reinforced plastics is sensitive to variations in the moisture content of the impregnated reinforcement at the time of pressing.

The interlaminar strength of voidless products made from a phènol‐formaldehyde resin in alcoholic solution with absorbent paper or scoured fabrics is substantially constant over the range of resin content likely to be used in practice. With both types of reinforcement the limiting strength of the resin itself is approached—but not fully attained—at a resin content of 27%. There is no essential difference between the strengths obtained with scoured fabrics or absorbent paper.

The beneficial effects of desizing and scouring are conclusively proved. While the scouring process used does not appear to be highly critical, desizing by itself is not an adequate pre‐treatment. Absence of twist in the threads of a fabric does not contribute to higher interlaminar strength.
High‐efficiency laboratory frac‐tionation. VI. The automatic control of still‐jacket temperature
Authors: Dixos O. C.
Published: July 2007

In a high‐efficiency laboratory fractionating eoIumn, the control of the temperature of the jacket is of considerable importance and the hcat input .may require frequent adjustment. It simple(and rclatively cheap) nutomatic device is described which makes use of air thermometers as the temperature‐sensitic. celements The pressurc difference between two thermometers alters aJercury level and makes electrical contacts which switch the heater on or off by means of a relay.
Temperature sensitivity of plasticizer‐polymer systems
Authors: Dyson A.
Published: July 2007

The mechanical propcrtics of a plasticized polymer are gencnlly admitted to depend to a large extent on the viscosity of the plasticizer. It is shown that the tempernture dependence of the viscosity of a plasticizer may be less than that of a polymer, and that the addition of a plasticizer to a polymer may reduce the sensitivity of the systcm. This conclusion is in opposition to a common interpretation of the viscosity thcory of plasticizer action, but is shown to bc in accordance with experiment.