bluuebunny/crossref_metadata_2025 huggingface dataset:
The combination of hydrogen and oxygen in contact with hot surfaces
Authors: Bone William Arthur , Wheeler Richard V.
Published: December 2006

The authors have made a systematic investigation of the slow combination of hydrogen and oxygen in contact with various heated surfaces, including porous porcelain, magnesia, metals such as gold, silver, platinum and nickel, and reducible oxides such as ferric oxide, nickel oxide, and copper oxide. In each case the moist gaseous mixture was circulated at a uniform speed over the surface, which was maintained at a constant temperature in the combustion tube of the “circulation apparatus” employed by the authors in their researches on the slow combustion of hydrocarbons.
Artificial double refraction, due to æolotropic distribution, with application to colloidal solutions and magnetic fields
Authors: Havelock Thomas Henry
Published: December 2006

In 1902 Majorana described some new effects observed on placing in a uniform magnetic field certain solutions of dialysed iron, such as that of Bravais. The solution was found to become doubly refracting like a positive or negative uniaxal crystal, with its axis parallel to the lines of magnetic force. A formal theory of the phenomena given by Voigt consisted in adding to the ordinary electrical equations terms of the second order, representing the action of the magnetic field upon the natural vibrations of the medium. Previously to these experiments, Kerr had obtained a negative double refraction in submitting to a magnetic field a medium composed of pure water containing invisibly fine particles of Fe
3
O
4
, his explanation of the effect being that the particles might be supposed to join together into filaments along the lines of magnetic force.
Stress-calculation in frameworks by the method of "systematic relaxation of constraints"—I and II
Authors: Southwell Richard Vynne
Published: December 2006

1―Framed structures, and the principles which govern their design, are familiar to all students of engineering science. Bending and twisting actions impose stresses which range between wide limits, but a straight bar in tension or compression sustains practically the same stress at every point; therefore economy of material can be attained by constructing frameworks from straight numbers, connected at their ends and so arranged that external forces (other than those arising from the weights of the members themselves) are applied only at the joints.

In theory we may (for a first approximation) neglect entirely the effects of fixity at the joints, and substitute for the actual framework a "skeleton diagram" in which every member is replaced by a line of thrust or tension. The problem then presented will be soluble by purely statical methods, or it will involve the elastic properties of the members, according as the number of these (
m
) is related to the number (
j
) of the joints. In a "plane frame" (where the external forces, as well as the lines of thrust or tension, are coplanar) the actions will be statically determinate if
m
= 2
j
- 3.(1)
The constitution and formation of bleaching powder
Authors: Bunn Charles William , Clark L. M. , Clifford I. L.
Published: December 2006

"Bleaching powder" is made by the action of chloride gas on calcium hydroxide, the reaction being essentially: 2Ca(OH)
2
+ 2Cl
2
→ Ca(OCl)
2
+ CaCl
2
+ 2H
2
O. The constitution of the solid formed in this way has been the subject of investigation and speculation for many years, since its properties are not those to be expected of a mixture formed according to the above equation. In the first place, the reaction represented by the above equation never goes to completion; commercial bleaching powder usually contains 15-25% of calcium hydroxide and only about 35% chlorine available for oxidation; while even under special laboratory conditions it is extremely difficult to reduce the calcium hydroxide content below 5%. Secondly, the physical properties of bleaching powder are not those of a simple mixture of calcium hypochlorite, calcium chloride and unreacted calcium hydroxide; for instance, ordinary bleaching powder is not markedly deliquescent, and therefore does not contain free calcium chloride.In the account which follows, no attempt is made to summarize the whole of the previously published work; references are given only to publications which appear to have immediate connection with the issues raised here.
Elastic and inelastic cross-sections of the mercury atom
Authors: Arnot F. L. , Baines G. O.
Published: December 2006

A considerable amount of experimental work has been done in investigating the total cross-section of an atom for collision with an electron in various gases. The total cross-section is measured by determining the number of electrons deflected out of a homogeneous beam, or which have their energy decreased, as the beam passes through the gas. For a complete knowledge of collision processes, it is necessary to know not only the total cross-section for collision but also the cross-section of the atom for various specific types of collision. The total cross-section can be divided into two main partial cross-sections—that for elastic collision and that for inelastic collision. The latter may be subdivided into the cross-section for excitation and the cross-section for ionization. The cross-section for excitation may then be further subdivided into the various cross-sections pertaining to the numerous discrete energy losses that the electron may suffer in its collision with the atom.
The optical properties of solids
Authors: Wilson Alan Herries
Published: December 2006

1—The theory of the optical constants of metals remained in the state in which it was left by Drude until Kronig applied the modern theory of metals to the problem. Since the appearance of Kronig's first paper many authors have tried to extend the theory so as to bring the finer effects within its scope, and we may sum up the present position as follows. In the infra-red the optical constants of metals vary with temperature, and are therefore very much influenced by the thermal vibrations of the solid. For frequencies in this region the existing theory is effectively the Drude theory which relates the optical constants to the conductivity in static fields and to the inertia of the electrons. This theory is satisfactory in the far infra-red, but fails in the near infra-red. In the visible and ultra-violet the optical constants are approximately independent of temperature, which means that the effect of the theory to be reasonably accurate, and we might hope to obtain useful information about the internal state of a metal. It must, however, be admitted that there is no really consistent theory extant, and, since our means of investigating the interior of a metal are very limited indeed, it seems desirable that the theory should be put upon as sound a basis as possible. It is the main object of this paper to give a critical discussion of the phenomenon in the visible and ultra-violet, the effect of the lattice vibrations being entirely neglected. In 2 the fundamental formula, which is a generalization of the Kramers-Heisenberg dispersion formula, is derived, and it shown that it is quite unnecessary to make the wave-length. In fact the problem becomes clarified if we do not make this assumption. It is also shown that there is no Lorentz-Lorenz correction to be introduced.
The viscosity of liquid helium
Authors: Wilhelm J. O. , Misener A. D. , Clark A. R.
Published: December 2006

It is a well-known fact that liquid helium changes from one form of liquid to another at a temperature of 2.19º K, under its own vapour pressure at that temperature. The liquid above this temperature is spoken of as helium I, and below it, as helium II. This temperature is known as the λ point. The apparent difference between these two forms of the liquid is that helium I visibly boils as it is being evaporated in a way similar to ordinary liquids, but immediately this temperature is passed boiling stops and the liquid appears to be absolutely quiescent, although the temperature is progressively reduced by continued evaporation. Many properties of these two forms of liquid helium have been studied, but apparently up to the present the viscosity has not been determined. In order to keep the liquid helium at a given temperature below 4.2º K, its boiling point, it is necessary to allow it to boil under reduced pressure, consequently the formation of bubbles excludes any possibility of using a capillary viscosimeter method. The necessity of operating the liquefying system under reduced pressure also allows small amounts of impurity to leak in; these traces of impurity condense over the liquid helium and drop as fine particles through the liquid. This has to be considered in designing the apparatus.
The relation between the alum structures
Authors: Lipson H.
Published: December 2006

That the crystals which comprise the alums form an isomorphous series has generally been accepted almost as a self-evident fact. This is due to similarity of their chemical formulae and of their crystal classes, and the evidence was rendered almost complete when Cork showed that a series ranging from ammonium alum to thallium alum was based on the one space-group, Pa3. There were, indeed, some discrepancies in his measurements, but these could be ascribed to small parameter differences. The first indication of polymorphism among the alums was given by methyl ammonium alum, of which the structure was found to be different from that of potassium alum. §
Statistical theory of turbulence III-Distribution of dissipation of energy in a pipe over its cross-section
Authors: Taylor Geoffrey Ingram
Published: December 2006

The success of the theory of turbulence given in Part I, in predicting the connection between the rate of dissipation of energy in turbulent motion and the shape of the Ky correlation curve, suggests that it may be possible to use measurements of correlation in order to find out how the dissipation of energy is distributed over a field of turbulent flow. This is a fundamental question in any theory of turbulent motion which attempts to penetrate beyond the stage of empirical assumptions. By a fortunate coincidence the necessary observations already exist for the analysis of one case of flow from this point of view. The rate o f dissipation of energy of turbulent flow is W = 7·5
μ
¯¯(∂
u
/∂
y
)
2
= 15
μ
¯
u
2
/λ
2
.
The nuclear photoelectric effect
Authors: Chadwick James , Goldhaber M.
Published: December 2006

Some time ago we reported in ‘Nature’ the observation of a nuclear photo-effect, the disintegration of the deutron by γ-rays. An effect of y-rays upon complex nuclei might be expected to occur from analogy with the phenomena of excitation and ionization of atoms by light, and such an effect has been looked for from time to time by various investigators. A necessary condition to make disintegration possible is that the energy of the γ-ray quantum must be greater than the binding energy of the particle which is to be removed from the nucleus. The most energetic γ-rays which are readily available in sufficient intensity are those of thorium C", which have an energy
hv
— 2·62 x 10
6
electron volts. One can hope, therefore, using these γ-rays, to produce disintegration with the emission of a heavy particle, such as a neutron, proton, etc., only in those nuclei which have a small or negative mass defect, such as the nuclei of deuterium, beryllium, and those radioactive elements which emit α-particles. In fact, only the nuclei of deuterium and beryllium have so far been disintegrated in this way. The disintegration of beryllium by the γ-rays of radium was first reported by Szilard and Chalmers. No evidence of a photo-electric disintegration amongst the radioactive elements has yet been found.
The emission spectrum of bismuth fluoride (BiF)
Authors: Howell H. G.
Published: December 2006

The most probable electron configuration of the lighter diatomic molecules and the order of their electrons binding have been determined by Mulliken, but no such systematic scheme has yet been formulated for the heavier molecules. The reason for this is not far to seek. the molecules whose structure can best be interpreted theoretically are H
2
and He

, and with these providing a secure foundation the successive addition of single electrons to them has enabled the configuration of the simpler molecules to be determined. This process, similar to the Atombau method used by Bohr, cannot be continued indefinitely as its successful working depends entirely on the existence of suitable molecular data. These are derived mainly from the vibrational and rotational analyses of band spectra and also from ionization potential experiments. At present comparatively few measurements have been made upon the spectra of heavy diatomic molecules and these have been used to provide vibrational analysis only. It is this incompleteness in the observational data that is hindering the construction of a reliable electronic scheme for these molecules. In building up the configuration of the members of such a series as AuF, HgF, TlF, PbF, and BiF where the atomic number of the metal radical increases by unity from member to member, the most that can be expected at first is a determination of the change in the binding force from molecule to molecule as the additional electron is added. This change can be followed by noting the change in the vibration frequency of each molecule in its ground state. This series was chosen on account of a very remarkable similarity in the general appearance of the spectra of PbF and BiF, which has been reported in a previous publication.
Investigations of Raman spectra III-Deuterium-substituted acetic acids
Authors: Angus William Rogie , Leckie Alan H. , Wilson Christopher L.
Published: December 2006

Isotopic substitution of deuterium atoms for protium atoms has now been carried out successfully for a widely different variety of substances, and the influence of isotopic substitution on various physical properties has been discussed in the literature. Spectroscopic effects have been investigated in several spectral regions but mostly by Raman effect measurements. Yet in no previous investigation have result been recorded for a substance in which deuterium substitution is made in two parts of the molecule simultaneously or separately. Such substitution is possible in carboxylic acids, and has been effected for the two "heavy" acetic acids whose investigation is reported in this paper. Substitution of deuterium for all protium atoms yielded trideuteracetic deuteracid (CD
3
CO
2
D), and replacement of the carboxyl protium only by deuterium resulted in the formation of acetic deuteracid (CH
3
CO
2
C). Not only do the Raman spectra of these acids differ from the spectrum of acetic acid (CH
3
CO
2
H) due to isotopic effects but, by comparing the three spectra, the actual assignment of the frequencies is rendered easier. In addition, the spectrum of "light" acetic acid has been examined, since there is a marked lack of agreement in existing data, and, for comparison purposes, the spectrum of acetic anhydride has also been investigated.
The two-dimensional hydrodynamical theory of moving aerofoils-II
Authors: Morris Rosa M.
Published: December 2006

1⋅1—In the first paper of this series (referred to subsequently as “I”) I developed in some detail the complete solution of the hydrodynamical problem of the motion of an incompressible homogeneous inviscid liquid when a cylinder with a general aerofoil cross-section is moving in any manner perpendicular to its axis. As was mentioned in that paper, the discussion there suffers from two well-known defects. In the first place it fails generally when there is a sharp edge to the moving cylinder—or a singularity on the boundary curve—because the velocity of the liquid, as defined by the potential function, becomes infinite at such an edge. This difficulty is usually surmounted by a proper choice of the circulation, but in the case of the moving cylinder this artifice is unavailing by itself as it only gives one condition, when the complete vanishing of the velocity at the trailing edge involves two. In any case, however, the existence of finite circulation creates difficulties of its own—the energy involved in such circulations is infinite—so that still further complication of the mathematical problem seems required. In practice it is known that the liquid motion is more complicated than that represented in the simpler problem, as it is always accompanied by the development, at such a sharp edge, and particularly in unsteady motion, of a region of turbulent motion in the fluid which trails behind in the wake of the cylinder. To deal with this wake and its effects mathematically we must, of course, make certain simplifying assumptions. The simplest picture is that used by Wagner (1925), who imagined the wake to be a simple surface of discontinuity (vortex sheet) trailing behind in the liquid. Of course, in a perfect fluid such a sheet could not arise, but nevertheless, by assuming its existence, it is possible without any close inquiry into its structure to calculate its effect on the forces acting on the cylinder. This is, in effect, what Wagner did, but under conditions which imply that his results are only approximately true when the cylinder is a flat plate with very small motion (without rotation). The main objects of the present paper are, first, to show that the general theory of the first paper can be extended to include the effects of such surfaces of discontinuity and, second, to discuss the bearing of the general results obtained in the particular problems discussed by Wagner, and others in extension of his work; and thereby to test the validity of the formulae now used in practice, the various terms in which have been obtained by diverse devices, all indirect and often involving contradictory physical assumptions and approximations.
An experimental determination of the spectrum of turbulence - With an appendix: method of deducing
F(n)
from the measurements.
Authors: Simmons L. F. G. , Salter C.
Published: December 2006

The experimental investigation of isotropic turbulent motion is most conveniently conducted in the air stream of a wind tunnel in which the turbulence is augmented by the addition of a grid of uniform mesh placed across it. At any point downstream, beyond the wind shadow of the grid, the velocity fluctuations are small compared with the mean speed of the stream, but vary irregularly with time. Records taken of
u
, the instantaneous value of the turbulent component in the direction of motion, show that the time variations follow the random law of errors (Simmons and Salter 1934; Townend 1934); but no successful attempts appear to have been made to analyse such a record into its harmonic components. On the other hand, by utilizing a hot-wire anemometer to produce a current proportional to
u
, and employing electrical filters to measure the contributions to
u
2
‾ which arise from frequencies within the range 0 to
n
where
n
is varied, data may be obtained from which a spectrum curve of the variation in velocity
u
, at a fixed point can be plotted. The ordinate of this curve at frequency
n
represents
F(n)
, the function denoting the probability of the existence of velocities between
n
and
n
+
dn
, whose significance is discussed by Professor G. I. Taylor in the paper which follows. In some experiments undertaken at Professor Taylor’s suggestion for the purpose of determining the values of
F(n)
for turbulence created by a grid of square mesh, the hot-wire technique was employed to measure
u
2
‾ from the readings of a thermal milliammeter, placed in the output circuit of a valve amplifier. In order to effect the analysis different electrical filters were successively put in the measuring circuit. Two types of filter were used: one, a
low-pass
, allowed the passage only of currents below a certain frequency; the other, a
high-pass
, only those above a certain critical frequency, the limit in each case being settled by the electrical constants of the filter. The former type served to explore the range 0-325 c./sec.; the latter was used for frequencies above this figure. From the ratios of readings of the milliammeter taken, in each case with and without the filter, it was possible to obtain, at any given wind speed, a close approximation to the spectrum curve required.
The probability of annihilation of positrons without emission of radiation
Authors: Massey Harrie Stewart Wilson , Burhop Eric Henry Stonely
Published: December 2006

There are two distinct processes by means of which a positron may be annihilated and the excess energy liberated in the form of radiation. These are: (1) Annihilation by a free electron. Here the energy must reappear in the form of at least two quanta to satisfy the conservation laws. (2) Annihilation by a bound electron. In this case the energy may appear in the form of a single quantum since the nucleus of the atom in which the electron is bound is available to take up excess momentum.
The photochemical polymerization of methyl acrylate vapour
Authors: Melville Harry Work
Published: December 2006

The investigation of the polymerization reactions of ethylene derivatives has defined fairly clearly the nature of the substituents most likely to favour such a reaction. For instance, it is absolutely essential to have a = CH
2
group at one end of the molecule, while the substituent attached to the other carbon atom at the end of the double bond may consists of a large variety of groups such as CH
3
, COOCH
3
, CN, halogen, CH = CH
2
, etc. In the methyl methacrylate molecule, CH
2
= C(CH
3
)COOCH
3
, both groups attached to the
α
-carbon atom are separately capable of favouring the tendency to form polymers, the methyl group probably making a contribution small compared with that of the carboxyl group since propylene is rather difficult t o polymerize. Consequently, if the methyl group is replaced by a hydrogen atom the ability of the molecule to polymerize should not be greatly altered. The experiments on the photo-polymerization of methyl methacrylate vapour (Melville 1937) have shown, however, that this methyl group may play an important part in determining what type of reaction stops the growth of the polymer and thereby limits its molecular weight. Indeed, it was suggested that the long life of the growing methacrylate polymer is entirely due to the immobility of the methyl group. This has the further consequence that the cross-linking of polymers, if branching could occur, should for the same reason be practically impossible-a suggestion compatible with the straight-chain characteristics of the methacrylate polymer. The question then arises as to what will happen when the methyl group is replaced by a relatively more mobile hydrogen atom. This paper is therefore concerned with the photo-polymerization of methyl acrylate vapour which has been carried out under similar conditions to those obtaining with the methacrylate.
Croonian Lecture: The insect as a medium for the study of physiology
Authors: Wigglesworth Vincent Brian
Published: December 2006

Insects live and feed, move, grow and multiply like other animals; but they are so varied in form, so rich in species, and adapted to such diverse conditions of life that they afford unrivalled opportunities for physiological study. The general problems of physiology are much the same in all groups of animals; and this lecture, which represents, in effect, an apology for the study of insect physi­ology, is an attempt to show that among the insects may be found material well suited for the solution of many of these problems. By human standards most insects are small in size, and this brings with it certain features which dominate their physiology. There is the same degree of functional specialization in their organs as there is in mammals; but they are made up of cells of the same dimensions as those in other animals—often, indeed, of cells which are larger than most. Each organ therefore contains far fewer cells, and the organization of their bodies must of necessity appear more simple. It is, however, a deceptive simplicity; for the range of physiological activities of which the single cell is capable is no less and may indeed be greater than it is in larger animals. On the other hand, their small size enables the insects to dispense with many of the physiological elaborations that are needed by mammals. Air-containing tracheae run direct to the tissues; and the high rates of metabolism which active insects develop can be met by the diffusion of gases along these tubes, supplemented in the most active forms by mechanical ventilation of the larger trunks or of the air sacs into which they are dilated.
Building epidemiological models fromR0: an implicit treatment of transmission in networks
Authors: Aparicio Juan Pablo , Pascual Mercedes
Published: December 2006

Simple deterministic models are still at the core of theoretical epidemiology despite the increasing evidence for the importance of contact networks underlying transmission at the individual level. These mean-field or ‘compartmental’ models based on homogeneous mixing have made, and continue to make, important contributions to the epidemiology and the ecology of infectious diseases but fail to reproduce many of the features observed for disease spread in contact networks. In this work, we show that it is possible to incorporate the important effects of network structure on disease spread with a mean-field model derived from individual level considerations. We propose that the fundamental number known as the basic reproductive number of the disease,R0, which is typically derived as a threshold quantity, be used instead as a central parameter to construct the model from. We show that reliable estimates of individual level parameters can replace a detailed knowledge of network structure, which in general may be difficult to obtain. We illustrate the proposed model with small world networks and the classical example of susceptible–infected–recovered (SIR) epidemics.
1200 years of regular outbreaks in alpine insects
Authors: Esper Jan , Büntgen Ulf , Frank David C , Nievergelt Daniel , Liebhold Andrew
Published: December 2006

The long-term history ofZeiraphera dinianaGn. (the larch budmoth, LBM) outbreaks was reconstructed from tree rings of host subalpine larch in the European Alps. This record was derived from 47 513 maximum latewood density measurements, and highlights the impact of contemporary climate change on ecological disturbance regimes. With over 1000 generations represented, this is the longest annually resolved record of herbivore population dynamics, and our analysis demonstrates that remarkably regular LBM fluctuations persisted over the past 1173 years with population peaks averaging every 9.3 years. These regular abundance oscillations recurred until 1981, with the absence of peak events during recent decades. Comparison with an annually resolved, millennium-long temperature reconstruction representative for the European Alps (r=0.72, correlation with instrumental data) demonstrates that regular insect population cycles continued despite major climatic changes related to warming during medieval times and cooling during the Little Ice Age. The late twentieth century absence of LBM outbreaks, however, corresponds to a period of regional warmth that is exceptional with respect to the last 1000+ years, suggesting vulnerability of an otherwise stable ecological system in a warming environment.
Early Cambrian origin of modern food webs: evidence from predator arrow worms
Authors: Vannier J , Steiner M , Renvoisé E , Hu S.-X , Casanova J.-P
Published: December 2006

Although palaeontological evidence from exceptional biota demonstrates the existence of diverse marine communities in the Early Cambrian (approx. 540–520 Myr ago), little is known concerning the functioning of the marine ecosystem, especially its trophic structure and the full range of ecological niches colonized by the fauna. The presence of a diverse zooplankton in Early Cambrian oceans is still an open issue. Here we provide compelling evidence that chaetognaths, an important element of modern zooplankton, were present in the Early Cambrian Chengjiang biota with morphologies almost identical to Recent forms. New information obtained from the lowermost Cambrian of China added to previous studies provide convincing evidence that protoconodont-bearing animals also belonged to chaetognaths. Chaetognaths were probably widespread and diverse in the earliest Cambrian. The obvious raptorial function of their circumoral apparatuses (grasping spines) places them among the earliest active predator metazoans. Morphology, body ratios and distribution suggest that the ancestral chaetognaths were planktonic with possible ecological preferences for hyperbenthic niches close to the sea bottom. Our results point to the early introduction of prey–predator relationships into the pelagic realm, and to the increase of trophic complexity (three-level structure) during the Precambrian–Cambrian transition, thus laying the foundations of present-day marine food chains.
On the similarities between radiation and mechanical strains
Authors: Bose Jagadis Chunder , Strutt John William
Published: December 2006

I have in the previous paper described the various interesting effects due to visible and electric radiation. Different considerations were adduced which tended to show that these effects were due to molecular strain, produced in the substance by the action of radiation. The whole history of the change produced by radiation—both the direct and after-effects—was graphically recorded in the various curves given. It was supposed that the strain effect on a, substance was attended with conductivity or electromotive variation. This supposition can be further verified by observing whether undoubted strain, which can be produced by mechanical means, does give rise to a conductivity or electromotive variation.
Some experiments in magnetism.
Authors: Porter T. C. , Strutt John William
Published: December 2006

For many years the writer has, from time to time, been engaged in studying the effect of a powerful magnetic field upon crystals in the act of their formation and growth. It seemed to him probable that if the molecules of substances have magnetic poles, they might group themselves differently when under the influence of a powerful magnetic field, thus producing an orientation of the crystals, or even an alteration in the form or optical characteristics of the crystals themselves. It seemed also possible that if the supposed polar properties of the molecules were the result of atomic polarity, a powerful external magnet might produce some appreciable effect in the chemical combination of the atoms, changing the rate of chemical reaction, if it did not change the character of the compounds formed.
On the distribution of stress and strain in the cross-section of a beam.
Authors: Morrow John , Hele-Shaw Henry Selby
Published: December 2006

Our knowledge of the strains produced in materials by different kinds and combinations of stress rests mainly on theoretical considerations. Much accurate experimental work has been done in the observation of direct tensile strains, but little attention has been given to the lateral strain accompanying a simple tensile or compressive strain, or to the lateral strain occurring in a bar under bending forces. The latter, indeed, has, perhaps, never before been measured in metal specimens.
Constant-standard silver trial-plates.
Authors: Matthey Edward , Crookes William
Published: December 2006

Referring to my paper communicated to the Royal Society, February 16, 1894, and read March 15, 1894, in which it was shown that moderately sized plates of sterling silver of a uniform standard could be obtained by casting from thin castings, my attention since then was drawn to the difficulty of casting larger quantities than those described in that paper, which were only of an average weight of 4 to 5 kilogrammes per plate, and to the desirability of obtaining a large plate, say of some 8 or 10 kilogrammes in weight, without difficulty, and I have therefore resumed my attention towards effecting this. It appears that considerable difficulties have been experienced with regard to obtaining large plates of constant standard. In the Royal Mint Report of 1873 is a memorandum appended by Professor W. Chandler Roberts, which refers to a series of well-known experiments with regard to obtaining a constant alloy of 0•900 silver by Levol in the Paris Mint, he himself being at the time engaged in the preparation of a standard silver trial-plate.
Physical constants at low temperatures. (1)—The densities of solid oxygen, nitrogen, hydrogen, etc.
Authors: Dewar James
Published: December 2006

1. The following experiments on the solid densities of oxygen, nitrogen and hydrogen were carried out as part of a former investiga­tion dealing with gaseous densities at low temperatures. The method adopted was to measure the volumes of the gases sucked into a cooled space of known capacity, when the temperature was such as in the first place to induce liquefaction and finally solidification. For such experiments to be successful the rate of liquefaction and the cooling must be under thorough control, otherwise the cooled space may not get completely filled with solid. Further, the volume of gas condensed ought to be as large as possible, in any case about 20 litres, in order to diminish errors inseparable from the mode of manipulation.
On the effect of a magnetic field on the rate of subsidence of torsional oscillations in wires of nickel and iron, and the changes produced by drawing and annealing.
Authors: Gray Andrew , Wood Alexander
Published: December 2006

On May 15th, 1902, we communicated to the Royal Society a paper entitled “ On the Effect of a Longitudinal Magnetic Field on the Internal Viscosity of Nickel and Iron, as shown by Change of the Rate of Subsidence of Torsional Oscillations". We described in that paper the results of experiments on the rates of subsidence of torsional oscillations in nickel and iron wires in fields of different strengths, and showed that the effect of the field, or, more properly, of the magnetisation of the wire, is to increase the rate of subsidence in nickel and to diminish it in iron.
A note on the action of radium on micro-organisms.
Authors: Green Alan B. , Foster Michael
Published: December 2006

The radium 'salt used in these experiments was 1 centigramme of radium bromide, bought of Messrs. Buchler and Co., of Brunswick, in June, 1903. It was contained in a vulcanite and brass capsule, fronted with thin talc.
Notes on the statolith theory of geotropism. I. Experiments on the effects of centrifugal force. II. The behaviour of tertiary roots.
Authors: Darwin Francis , Pertz D. F. M.
Published: December 2006

According to the statolith theory, there are in plants certain cells specialised to act as organs of orientation in space; organs, in fact, functioning like the otocysts of certain animals. In both cases the sense of verticality is believed to be the result of the pressure of certain heavy bodies (usually starch grains in the case of plants), on a sensitive surface, namely, the lining membrane of the otocyst in the case of animals, or in the case of plants the protoplasm lining the statolith-containing cells (statocytes). In a paper dealing with the arguments for and against the theory, Jost brings forward as the most serious objection the behaviour of plants to centrifugal force.
Studies on enzyme action. II.—The rate of the change, conditioned by sucroclastic enzymes, and its bearing on the law of mass action.
Authors: Armstrong Edward Frankland , Armstrong Henry Edward
Published: December 2006

Although it is now universally recognised that enzymes play a most important part in animal and plant metabolism and that they even condition synthetic changes, most of the work done has been of a qualitative character; in only a few cases has the nature of the action been precisely determined—and the results arrived at in these few cases, if not discrepant, cannot easily be harmonised at first sight. C. O’Sullivan and Tompson were the first to study the action of enzymes quantitatively.
Effects of environmental and operational variability on structural health monitoring
Authors: Sohn Hoon
Published: December 2006

Stated in its most basic form, the objective of structural health monitoring is to ascertain if damage is present or not based on measured dynamic or static characteristics of a system to be monitored. In reality, structures are subject to changing environmental and operational conditions that affect measured signals, and these ambient variations of the system can often mask subtle changes in the system's vibration signal caused by damage. Data normalization is a procedure to normalize datasets, so that signal changes caused by operational and environmental variations of the system can be separated from structural changes of interest, such as structural deterioration or degradation. This paper first reviews the effects of environmental and operational variations on real structures as reported in the literature. Then, this paper presents research progresses that have been made in the area of data normalization.
Bragg grating-based fibre optic sensors in structural health monitoring
Authors: Todd Michael D , Nichols Jonathan M , Trickey Stephen T , Seaver Mark , Nichols Christy J , Virgin Lawrence N
Published: December 2006

This work first considers a review of the dominant current methods for fibre Bragg grating wavelength interrogation. These methods include WDM interferometry, tunable filter (both Fabry–Perot and acousto-optic) demultiplexing, CCD/prism technique and a newer hybrid method utilizing Fabry–Perot and interferometric techniques. Two applications using these techniques are described: hull loads monitoring on an all-composite fast patrol boat and bolt pre-load loss monitoring in a composite beam in conjunction with a state-space modelling data analysis technique.
A letter of Dr. John Wallis to Robert Boyle Esq; concerning the said doctor's essay of teaching a person dumb and deaf to speak, and to understand a language; together with the success thereof: which letter though written many years since, was but lately obtain'd to be inserted here, it being esteemed very well worth to be preserv'd and communicated for publick use
Authors: Wallis John
Published: December 2006

Sir, I Did acquaint you a while since, That (beside the consideration of...., which I had in hand;) I had undertaken another Task, (almost as hard as to make Mr.... understand Reason,) to Teach a person
Dumb
and
Deaf
, to
speak
and to
Understand a Language
.
The ingenieus reflexions relating to medical springs numb. 52, considered. The palpable indications of same healing springs remarked; with an account of some such springs in England, which do confirm the indications; and of others obiter; By Dr. J. Beale to the publisher: which discourses were in N. 56. omitted for want of sufficient room, not without injury to the author, who had designed these communications for another prop, specifying by manifest observations, how terrestrial steames may be the generati
Authors: Beale John
Published: December 2006

In pursuance of what I offered
(Numb. 56.)
concerning
Mineral
Springs, I proceed to the Ingenious Reflexions made
Numb. 52
on the Breviate of
Dr. Witties
Defence
,
which is in your
Tract 51;
With no Intention at all to affront the worthy Authors modest Suggestions; but to represent matter of Fact, and manifest Observation, which may chance to satisfy some of his Inquiries; And to give more Light to my forementioned Arguments
.
Some considerations of Mr. Nic. Mercator, concerning the geometrick and direct method of signior Cassini for finding the apogees, excentricities, and anomalies of the planets; as that was printed in the Journal des Scavans of Septemb. 2. 1669: which considerations are here delivered in a Latine tongue, wherein they were written by the author, as chiefly regarding the learn'd in astronomy, viz
Authors: Mercator Nicolas
Published: December 2006

Clarissimi
Cassini
Methodus
Investigandi Apogéa, Excentricitates & Anomalias Planetarum, breviter Exposita & Demonstrata.
Supponit Cl. Cassinus, ad Planetam in Ellipsi moventem extendi ab utroque foco rectas, quarum altera sit
medii
, altera autem
veri
motûs linea. Constructio porro tails est;
An account of three books. - I. Esperienze intorno alla generatione degl’ insetti, fatte da francisco Redi, academico della Crusca. ln Firenze, A. 1668. in 40. II. Pharmacopocia regia, sive dispensatorium novum locupletatum & absolutum, cum annexa mantisla spagyrica, & gemino discursu apologetico contra ott. Tachenium, & Franc. Vernis. Auth Joh Zwelser. M. D. A. 1668. in folie. III. Affectionum quœ dicuntur hysterica & hypochondriacœ pathalogia spasmodica vindicata, contra responsion. episto
Authors: Redi Francesco , Zwelser Joh , Willis Thomas
Published: December 2006

An account of three books. - I. Esperienze intorno alla generatione degl’ insetti, fatte da francisco Redi, academico della Crusca. ln Firenze, A. 1668. in 40. II. Pharmacopocia regia, sive dispensatorium novum locupletatum & absolutum, cum annexa mantisla spagyrica, & gemino discursu apologetico contra ott. Tachenium, & Franc. Vernis. Auth Joh Zwelser. M. D. A. 1668. in folie. III. Affectionum quœ dicuntur hysterica & hypochondriacœ pathalogia spasmodica vindicata, contra responsion. epistol. Nathanaelis Highmori M. D. cui accessere exercitat. Medico-physicœ duœ, I. De Sanguinis Accension. 2. De Motu Musculari, Auth. Tho. Willis M. D. Nat. Philos. Prof. Oxon, nec non med. Coll. Londini & Soc. Regiæ Sodalis. Londini apud Jac. Allestry in 4°. The Learned and Ingenious Author of this Book, lately come to the Publishers hands, though not yet (which is much disliked by the curious) into our Stationers Shops.
Observations on insects, lodging themselves in old willows, produced before the Royal Society by Dr. Edmund King, July 14. 1670
Authors: King Edmond
Published: December 2006

You may remember, that about the
beginning
of
May
last, a piece of old Willow-wood, being sent me from Sir
John Bernhard
out of
Northamptonshire
, was produced before you; in which were lodged many Insects curiously wrapt up in green Leaves,in several channels or burrows, each with 12. 14. or 16. leaves round the Body, and several of them with as many little round bites of leaves at each end, to stop them up close.
The epistle dedicatory
Authors: Oldenburg Henry
Published: December 2006

Sir,
Having begun this New Century of the
Philosophical Transactions
near the time, that your Merits raised you to that eminent place you are now posses'd of; and considering also the steddy inclinations, you do on all occasions express to advance the Ingenuous Arts: For these to present you with the first Volume of these my new beginnings.
An extract of Monsieur Hevelius's letter, lately written to the Publisher, concerning the famous Kepler's manuscripts; together with some considerations of his, about the use of telescopic sights in astronomical observations: Delivered in the same language, wherein 'twas written
Authors: Hevelius Johannes
Published: December 2006

Ex
tuis
16 Septemb.
datis intellexi, Te pleniorem informationem de
Kepleri
Manuscripts desiderare
.
Brief directions how to tan leather according to the new invention of the Honourable Charles Howard of Norfolk, experimented and approved of by divers of the principal tanners using Leaden-hall market.
Authors: Howard Charles
Published: December 2006

Every part of the Oak-tree, of what age or growth soever, and all Oaken Copice-wood, of any age or size, being cut and procured in Barking time, will tan all sorts of Leather as well, at least, as Bark alone.
A continuation of Dr. Daniel Coxe's discourse begun in Numb. 107. touching the Identity of all volatil salts and vinous spirits; together with two surprising experiments concerning vegetable salts, perfectly resembling the shape of the plants, whence they had been obtained
Authors: Coxe Daniel
Published: December 2006

That which hath been said of
Alcalizate
Salts, may likewise be affirm'd concerning
Volatil Salts
, and
Vinous Spirits
:
Some observations and experiments made, and in a letter communicated to the publisher, for the R. Society, by the learned and inquisitive Mr. Martin Lister
Authors: Lister Martin
Published: December 2006

I Shall venture to entertain you at present with a few loose Notes, which you will be pleas'd to take in good part, and dispose of them as you think fitting.
Extracts of three letters : The one of M. Hugens, about a new invention of very exact and portative watches, serving to find the longitudes both at sea and Land: The second, of Dr . Swammerdam, touching an un-usual rupture of the the mercentery: The third, containing some observations of Mr. Lister about the star-stones ; together with Mr Rays annotations thereon.
Authors: Huygens Christian , Swammerdam  , Lister Martin
Published: December 2006

The watches of this Invention being made in small, shall serve for very exact Pocket-watches, and when made greater, shall be useful every where else and particularly to find the Longitudes both by Sea and Land, forasmuch as their movement is regulated by a principle of Equality, as that of Pendulum's is Cycloid, and that no kind of carriage shall be able to stop them.
An extract of a letter, written to the Publisher by Mr. J. L. about poisonous fish in one of the Bahama Islands
Authors: Larsen J.
Published: December 2006

Sir, I Do here with send you an account, I lately received from
New-Providence
, one of the
Bahama
Islands, concerning
Fish
there, which is as followeth;
A letter written to the Publisher by the Learned Mr. Ray, containing some considerations on the conjecture in numb. 114. of these tracts, about the swimming bladders in fishes
Authors: Ray
Published: December 2006

Sir, I was much pleased and satisfied with the ingenious conjecture I found in your
Transactions
of
May
last,
pag
. 310. concerning the swimming Bladders of Fishes.
Microscopical observations of Mr. Leewenhoeck, concerning the optic nerve, communicated to the publisher in Dutch, and by him made English.
Authors: Leeuwenhoek Antoni Van
Published: December 2006

Having acquainted Dr. Schravesande, that I could perceive no cavity in the optic nerve, he told me, that Galen had on a clear sun shiny day seen a hollowness therein, encouraging me to view that nerve again with more attention.
A continuation of the experiments made by Monsieur Hugens, and M. Papin, in the air pump; which are about the preservation of bodies
Authors: Hugens  , Papin M.
Published: December 2006

To know, whet her the
Vacuum
would be of use to the
Preservation of Bodies
, I took an Apple, and included it with such a
cover
, as is described formerly in our Method of taking away an exhausted Recipient from off the Engin.
An observation of the beginning of the lunar eclipse which hapned Aug. 19. 1681. in the morning, made on the Island of St. Lawrence or Madagascar
Authors: Heathcot Tho.
Published: December 2006

Mr.
Heathcot
was Chyrurgeon to a Ship which lay then at the bottom of a deep
Bay
on the
Western shore
of the
Island
, and that part which the
Portugese
and our Maps call the
Terra del Gada
, he had with him then on Shore, a
Quadrant
of 2 Foot
Radius
, and a
Telescope
of 9 Foot, but no Clock;
Succincta historiola, de tribus conjunctionibus magnis Saturni scilicet jovis nec non Martis, Gedani exeunte anno 1682. & initio anni 1683. ad 28. Maiist. n. usque, à Johanne Hevelio observatis
Authors: Hevelius Johannes
Published: December 2006

Mense Septembri anni præcedentis 1682. cùm
cometa
sese oculis nostris prorsùs subduxisset, cœpi tres superiores
Planetas Saturnum Jovem & Martem
, qui haud multùm ab invicem distabant, atque ad
conjunctionem
ergebant, aliquant crebrius & diligentius, â die scilicet 17
Sept
.
Joh. Hevelii historiola cometæ anni 1683
Authors: Hevelius Johannes
Published: December 2006

Plurimi sine dubio, imprimis ij, quibus Historia, Cometarum non adeo plane cognita est, haud parum mirabuntur, quod ab Anno 1680, in tribus sc.