bluuebunny/crossref_metadata_2025 huggingface dataset:
Output and unemployment dynamics in the United States: 1950–1985
Authors: Evans George W.
Published: July 2007

For US data over 1950–1985 the stochastic components of GNP growth and the unemployment rate appear to be stationary, and there is substantial feedback between these variables. The unconditional mean rate of unemployment in a joint model thus provides a natural benchmark in discussions of the ‘business cycle’. A bivariate VAR model is used to describe output–unemployment dynamics, to estimate the degree of persistence of output innovations, and to decompose output into trend and cycle. The bivariate results are interpreted using a restricted VAR and it is shown that a closely related cyclical measure can be obtained directly from the Okun's Law equation.
Models of military expenditure
Authors: Smith R. P.
Published: July 2007

A brief review of the extensive empirical literature devoted to explaining levels of military expenditure indicates a wide variety of unreconciled results. However, comparing the alternative models is not straightforward. This paper uses British post‐war military expenditures to illustrate some of the methodological issues involved in model comparison, evaluation and selection. Starting from two published models for the UK, a systematic specification search leads to a new model, which dominates alternative specifications, passes a wide range of misspecification tests, and also fits well to French data.
Seasonal adjustment and measuring persistence in output
Authors: Jaeger Albert , Kunst Robert M.
Published: July 2007

We examine the robustness of persistence measurement to different seasonal adjustment procedures. The empirical analysis is based on US data for real gross national product (GNP). Officially published data on US GNP are seasonally adjusted by Census X‐11. We find that this series gives significantly higher measures of persistence than GNP data adjusted by alternative seasonal adjustment methods. Some Monte Carlo evidence in support of this conclusion is also presented.
On measuring economic efficiency
Authors: Kalirajan K. P.
Published: July 2007

This paper considers a system consisting of a production frontier and factor share equations to measure firm‐specific technical efficiency and input‐specific allocative efficiency simulataneously. In estimating the system as a whole, the joint distribution of all errors in the equations is used. This is more efficient than using the marginal distribution of a function of the errors as one does by estimating either the profit function of the production function alone. The workability of the method is illustrated by applying it to farm‐level data from Philippines agriculture.
The measurement of rationing and the treatment of structural change in the uk mortgage market
Authors: Meen Geoffrey P.
Published: July 2007

UK mortgage markets have undergone major structural changes in the past few years, resulting in mortgages no longer being rationed. The ending of rationing has implications for the specification of empirical models of housing demand. Housing models have never adequately resolved how to incorporate unobservable mortgage rationing. Conventional proxy methods are particularly unsuitable, when rationing ceases. In this paper, we propose a new way of measuring rationing directly, which incorporates regime switching. The model of rationing is extensively tested and estimates of rationing for the period 1963–1988 are provided; these may be easily incorporated into housing demand studies.
The dynamics of job separation: The case of federal employees
Authors: Black Matthew , Moffitt Robert , Warner John T.
Published: July 2007

In this paper we develop a model of workers' quit decisions. Using panel data on a sample of US Federal government employees we use maximum‐likelihood techniques to determine how much of the observed decline in quits with job tenure is a result of declining individual quit propensities (‘state dependence’) rather than dynamic sample self‐selection (‘heterogeneity’). The latter is found to be much more important than the former. The effects of relative Federal government wages and other variables on quits are also estimated. The results are useful for analysing Federal compensation policies.
Purchasing power parity as a long‐run relation
Authors: Patel Jayendu
Published: July 2007

Dickey–Fuller and Stock–Watson tests of purchasing power parity (PPP) as a long‐run proposition are provided within the cointegration framework proposed by Granger. Since different countries use different weights to construct price indices, the traditional constraint that the coefficients on the price indices should be unity in the log‐linear PPP relation is relaxed. The absence of a general PPP relation cannot be rejected. At most, a PPP relation is indicated in five out of fifteen country pairs that are examined. Even if a long‐run PPP relation exists, it is not found to be useful in predicting future nominal exchange rates, which is consistent with efficient speculative markets.
Wage and price adjustment in a multimarket disequilibrium model
Authors: Salanie Bernard
Published: July 2007

The estimation of wage and price adjustment equations rests heavily on the use of tension variables that aim at capturing the disequilibria in the labour and goods markets. Disequilibrium models therefore provide a natural way of endogenizing these tension variables. This paper estimates jointly a two‐market disequilibrium model and a wage and price adjustment block where price and wage growth react to excess effective demands. The estimation is carried out using the simulated pseudo‐maximum‐likelihood methods developed by Laroque and Salaniè (1989); the results look promising as regards the estimation of even more sophisticated models.
The effect of parameter uncertainty on forecast variances and confidence intervals for unit root and trend stationary time‐series models
Authors: Sampson Michael
Published: July 2007

In this paper I describe the effect of parameter uncertainty on the way conditional forecast variances grow as the forecast horizon increases. Without parameter uncertainty, forecast variances for the unit root model grow linearly with the forecast horizon while with the trend stationary model they are bounded. With parameter uncertainty, however, I find that for both the unit root and the trend stationary models, forecast variances grow with the square of the forecast horizon so that uncertainty grows at a much faster rate than without parameter uncertainty.
An application and test for a random coefficient model in Bangladesh agriculture
Authors: Hoque Asraul
Published: July 2007

This paper deals with efficiency question by estimating four production functions for four different regions in connection with Bangladesh agriculture. Hildreth and Houck's (1968) random coefficient method was found more suitable than OLS after conducting an appropriate test for this. In contrast to earlier studies, 24 piece‐wise regressions have been fitted for each index of efficiency considering all four regions and six different ranges of farm size instead of a single regression so that the relationship could be studied more closely. The study clearly indicates higher efficiency for smaller farms.
Elasticity of substitution, technical progress and returns to scale in branches of Soviet industry: A new CES production function approach
Authors: Bairam Erkin
Published: July 2007

This study introduces and tests a new CES production function approach using data from five major branches of the Soviet industrial sector. The estimated equations obtained suggest that the Cobb‐Douglas production function is the appropriate production function for all branches under consideration except Food Processing.
Term structure of interest rates in the Singapore Asian dollar market
Authors: Lee Tom K. Y. , Tse Y. K.
Published: July 2007

This paper investigates empirically the term structure of interest rates in the Singapore Asian Dollar Market. We consider extended versions of the ARCH‐M model of Engle, Lilien, and Robins (1987). The extended models permit autocorrelation, skewness and leptokurtosis in the residuals. The robustness of the empirical tests with respect to alternative specifications of the ARCH process is examined. It turns out that there is significant time‐varying term premium, and this conclusion is independent of the hypothesized ARCH model.
Expenditure allocation across nondurables, services, durables and savings: An empirical study of separability in the long run
Authors: Anderson G. J.
Published: July 2007

The separability of categories of consumption expenditures and savings are empirically examined in the context of an error‐correction model of aggregate quarterly expenditure allocations in Canada. Some evidence is found for separability of consumption allocations from savings in both the long run structure and short run dynamics of the model lending some support to the use of the assumption in modelling consumption behaviour.
Models for truncated counts
Authors: Grogger J. T. , Carson R. T.
Published: July 2007

This paper examines a class of maximum‐likelihood regression estimators for count data from truncated samples. Estimators for the truncated Poisson and negative binomial distributions are illustrated. Simulation results are given to illustrate the magnitude of the bias that may result from the failure to account for overdispersion in truncated samples. An empirical application based upon the number of recreational fishing trips taken by a sample of Alaskan fishermen is provided.
The limiting distribution of extremal exchange rate returns
Authors: Hols Martien C. A. B. , De Vries Casper G.
Published: July 2007

Several nonnested fat‐tailed distributions have been advocated for modelling exchange rate returns. Instead of directly estimating these nonnested distributions we investigate the extremal distribution of the returns. The advantage is that the parameter which characterizes the amount of tail fatness can be estimated without maintaining a specific distribution, and hence enables one to test hypotheses. The parameter of the limit law is estimated by employing nonparametric procedures based on order statistics. The appropriateness of these procedures is assessed. Given this estimate one can derive bounds on the returns for very low probabilities on an excess. Such information is useful in evaluating the volatility of exchange rates.
Time aggregation and the distributional shape of unemployment duration
Authors: Bergström R. , Edin P.‐A.
Published: July 2007

This paper reports empirical evidence on the sensitivity of unemployment duration regression estimates to distributional assumptions and to time aggregation. The results indicate that parameter estimates are robust to distributional assumptions, while estimates of duration dependence are not. Time aggregation does not seem to have drastic effects on the estimates in a simple parametric model like the Weibull, but can produce dramatic changes in the more complicated extended generalized gamma model. Semiparametric models for grouped data produce stable estimates, and perform much better than continuous‐time models in terms of significance at high levels of time aggregation.
Classification and aggregation: An application to industrial classification in cps data
Authors: Cotterman R. , Peracchi F.
Published: July 2007

In this paper we offer a method for deciding how to aggregate a set of elementary industries. The method is then applied to the problem of estimating a wage equation that allows for industry‐specific effects. Our method explicitly formalizes the trade‐off between goodness‐of‐fit and parsimony implicit in an aggregation problem. By varying the parameter of the assumed loss function, one obtains a whole sequence of aggregation levels. Further, the resulting sequence is consistent; that is, groupings formed at one level of aggregation will never be undone when one aggregates further.
The relationship between forecast dispersion and forecast uncertainty: Evidence from a survey data—arch model
Authors: Rich R. W. , Raymond J. E. , Butler J. S.
Published: July 2007

This paper examines empirically the relationship between measures of forecast dispersion and forecast uncertainty from data on inflation expectations from the Livingston survey series and the Survey Research Center (SRC) survey series. Because the survey series do not provide probabilistic forecasts of inflation, we derive measures of inflation uncertainty by modelling the conditional variance of the inflation forecast errors from the survey series as an autoregressive conditional heteroscedastic (ARCH) process. The analysis is complicated by the fact that the overlap of forecast horizons for the survey series does not preclude the model's disturbance terms from displaying autocorrelation, and also places a restriction on the specification for the ARCH measures of inflation uncertainty. We estimate the model using Hansen's (1982) generalized method of moments (GMM) procedure to account for the presence of serial correlation and conditional heteroscedasticity in the disturbance terms. The results generally support the hypothesis that the measures of forecast dispersion across survey respondents are positively and statistically significantly associated with the measures of inflation uncertainty. However, the appropriateness of using forecast dispersion measures as proxies for inflation uncertainty is sensitive to the choice of the survey series.
Market structure and spells of employment and unemployment: Evidence from the construction sector in Egypt
Authors: Tunali Insan , Assaad Ragui
Published: July 2007

This paper investigates the links between market structure and spells of employment and unemployment in the construction sector in Egypt using an augmented job search framework. Two key features of the model are the reservation frontier which allows for a trade‐off between wages and expected duration of employment, and the dependency of unemployment durations on expected employment durations and expected wages. These, as well as conjectures concerning the influence of demand‐side forces obtained from the expressions for the transition rates out of employment and unemployment, are examined using Weibull, log‐logistic and generalized gamma parameterizations of the hazard rate. The parametric assumptions are exploited to resolve problems associated with selectivity and use of generated regressors.
Simple tests for sample selection bias in censored and discrete choice models
Authors: Vella F.
Published: July 2007

This paper presents two simple tests of sample selection bias for models where the primary equation of interest has a censored or discrete dependent variable. The first test is derived as a conditional moment test and can be implemented in a regression‐based framework. The second test is an extension of the testing procedures proposed by Heckman (1979) and Vella (1993) and is a t‐test on a constructed variable in an auxiliary equation. The utility of the tests is illustrated in a model determining the receipt of work conditioned nonwage labour income over a subsample of working women.
News effects in a high‐frequency model of the sterling‐dollar exchange rate
Authors: Goodhart C. A. E. , Hall S. G. , Henry S. G. B. , Pesaran B.
Published: July 2007

This paper uses an extremely high frequency data set on the dollar‐sterllng exchange rate to investigate the impact of news events on the very short‐term movements in exchange rates. The data set is a continuous record of the quoted price for the exchange rate on the Reuters screen. As such it records some 130,000 observations over an 8‐week period. The paper investigates the time‐series properties of the data using orthodox regression models, and then by making allowance for a time‐varying conditional variance. The conclusions vary significantly in moving to this more sophisticated model. The exercises are repeated now incorporating news announcement effects, letting these affect the level of the exchange rate and then the conditional variance process. Again it is found that the conclusions are radically altered in moving to the increasingly sophisticated model.
Joint tests for regularity and autocorrelation in allocation systems
Authors: Deschamps P. J.
Published: July 2007

In the context of allocation models with vector autoregressive errors we propose a convenient procedure, based on the Lagrange multiplier principle, for testing any possible combination of absence of serial correlation, homogeneity, and symmetry against any possible alternative which specifies autocorrelation of an arbitrary given order. We also derive generic expressions for the maximum likelihood estimation of the models under six possible combinations of constraints. The methodology is illustrated with the Rotterdam model and the differential AIDS model, both estimated from the same quarterly British data.
Detrending, stylized facts and the business cycle
Authors: Harvey A. C. , Jaeger A.
Published: July 2007

The stylized facts of macroeconomic time series can be presented by fitting structural time series models. Within this framework, we analyse the consequences of the widely used detrending technique popularised by Hodrick and Prescott (1980). It is shown that mechanical detrending based on the Hodrick–Prescott filter can lead investigators to report spurious cyclical behaviour, and this point is illustrated with empirical examples. Structural time‐series models also allow investigators to deal explicitly with seasonal and irregular movements that may distort estimated cyclical components. Finally, the structural framework provides a basis for exposing the limitations of ARIMA methodology and models based on a deterministic trend with a single break.
Gauss and matlab: A comparison
Authors: Rust J.
Published: July 2007

I compare two high‐level matrix programming languages with built‐in function libraries and graphics routines. Their interactive nature and convenient syntax makes them ideal for use in econometric applications. The languages are remarkably similar in terms of their features and performance. MATLAB's chief advantage is that it runs on a wider array of hardware and operating systems than GAUSS. GAUSS's main advantage is that it has better coverage of statistical and econometric routines. Overall, MATLAB's features seem best suited for analysing time‐series data and other macro econometric applications, while GAUSS is ideal for analysing panel data and other microeconometric applications.
A latent class poisson regression model for heterogeneous count data
Authors: Wedel M. , Desarbo W. S. , Bult J. R. , Ramaswamy V.
Published: July 2007

In this paper an approach is developed that accommodates heterogeneity in Poisson regression models for count data. The model developed assumes that heterogeneity arises from a distribution of both the intercept and the coefficients of the explanatory variables. We assume that the mixing distribution is discrete, resulting in a finite mixture model formulation. An EM algorithm for estimation is described, and the algorithm is applied to data on customer purchases of books offered through direct mail. Our model is compared empirically to a number of other approaches that deal with heterogeneity in Poisson regression models.
Estimating consumer preferences using market data—an application to us automobile demand
Authors: Arguea N. M. , Hsiao C. , Taylor G. A.
Published: July 2007

This paper explores the possibility of using market data to identify consumer preferences. A utility function composed of ‘homogeneous’ characteristics and goods‐specific effects is used as a basic link between the goods space and the characteristics space. The functional form for the hedonic price equation, the data requirements and issues of measurement errors for estimating demand and supply of characteristics are discussed. We illustrate the methodology by considering the US automobile demand using 1969–86 data compiled from Consumer Reports and Ward's Automotive Yearbook.
A univariate analysis of EMS exchange rates using a target zone model
Authors: De Jong F.
Published: July 2007

The models in the literature on exchange‐rate target zones imply a non‐linear time series model for the exchange rate. We show how the parameters of such models can be estimated and develop Maximum Likelihood and Method of Simulated Moments estimators for the target zone model of Krugman (1991). The Maximum Likelihood estimator is based on a computationally attractive approximation to the exact predictive density of the continuous time model. Monte Carlo experiments are used to assess the properties of this estimator. In the empirical part we estimate the model with data on recent EMS exchange rates. We find that the Krugman (1991) target zone model is not able to explain the full observed kurtosis and conditional heteroscedasticity of the exchange‐rate returns.
Economic fluctuations, market power, and returns to scale: Evidence from firm‐level data
Authors: Chirinko R. S. , Fazzari S. M.
Published: July 2007

Recent research on aggregate fluctuations, coupled with ongoing work in industrial organization, has renewed interest in the existence, magnitude, and cyclical pattern of market power and the extent of increasing returns to scale. By exploiting restrictions from dynamic theory and information from financial markets, we present a framework for generating quantitative evidence on market power and returns to scale. Tailoring the econometric model to firm‐level panel data, we calculate the percentage differential between price and marginal cost (the Lerner index) in terms of the parameters from the econometric system. Results for firms in eleven industries indicate that there is a great deal of heterogeneity in the extent of market power. Industries with significantly positive Lerner indices tend to have substantial increasing returns in the production technology. We find that there is only a modest relation between our estimated Lerner indices and traditional measures of market power and that, when market power varies temporally, it is usually procyclical. Thus, variations in the markup of price over marginal cost may help dampen aggregate economic fluctuations.
Estimation of econometric models of some discrete games
Authors: Kooreman Peter
Published: July 2007

This paper discusses, estimates and compares some microeconometric models for simultaneous discrete endogenous variables. The models are based on the assumption that observed endogenous variables represent the outcome of a static discrete game. I discuss models based on non‐cooperative equilibrium concepts (Nash, Stackelberg), as well as models which presume Pareto optimality of observed outcomes. The models are estimated using data on the joint labor force participation decisions of husbands and wives in a sample of Dutch households.
Attrition in longitudinal panel data and the empirical analysis of dynamic labour market behaviour
Authors: Van Berg G. J. Den , Lindeboom M. , Ridder G.
Published: July 2007

In the empirical analysis of unemployment durations and job durations, it is generally assumed that the stochastic processes underlying labour market behaviour and the behaviour concerning participation in a panel survey are independent. However, there are reasons to believe that the probability of dropping out of the panel is related to the rate at which a (different) job is found. If there is such a relation, and if it is ignored, then the estimator of the rate at which individuals become employed or change jobs will generally be inconsistent. In this paper we analyse the relation between the duration spent in a particular labour market state and the duration of panel survey participation, by explicitly modelling and estimating the joint distribution of both durations. The emphasis will be on models allowing for stochastically related unobserved determinants of both types of duration. We estimate models both for unemployment durations and for job durations.
Nonnegativity constraints and intratemporal uncertainty in a multi‐good life‐cycle model
Authors: Adang Pim , Melenberg Bertrand
Published: July 2007

In the standard multi‐good life‐cycle consumption model (with intertemporal additive utility) the intratemporal relations between the marginal utilities of the different goods are deterministic. However, these deterministic identities will not usually be satisfied by the data. To avoid these deterministic relationships, we apply an approach which consists of introducing intratemporal uncertainty, and which is, in particular, interesting when additional nonnegativity constraints are present. We estimate some simple versions of the model with this so‐called intratemporal uncertainty. The estimation results are, in general, in accordance with the theory, and most versions of the model are not rejected by Hansen and Singleton's misspecification test.
Forecasting in cointegrated systems
Authors: Clements Michael P. , Hendry David F.
Published: July 2007

We consider the implications for forecast accuracy of imposing unit roots and cointegrating restrictions in linear systems ofI(1) variables in levels, differences, and cointegrated combinations. Asymptotic formulae are obtained for multi‐step forecast error variances for each representation. Alternative measures of forecast accuracy are discussed. Finite sample behaviour in a bivariate model is studied by Monte Carlo using control variables. We also analyse the interaction between unit roots and cointegrating restrictions and intercepts in the DGP. Some of the issues are illustrated with an empirical example of forecasting the demand for M1 in the UK.
Semi‐parametric estimation of simultaneous equations with limited dependent variables: A case study of female labour supply
Authors: Lee Myoung‐Jae
Published: July 2007

We propose a general strategy to estimate semi‐parametrically simultaneous equations with limited dependent variables. First, each reduced form (RF) is estimated with various semi‐parametric methods. Second, the specification of each RF is tested to select an appropriate method. Third, the structural form (SF) equations are estimated using minimum distance methods and the restrictions among the SF and RF parameters. A case study of female labour supply is presented.
Forecasting exchange rates using feedforward and recurrent neural networks
Authors: Kuan Chung‐Ming , Liu Tung
Published: July 2007

In this paper we investigate the out‐of‐sample forecasting ability of feedforward and recurrent neural networks based on empirical foreign exchange rate data. A two‐step procedure is proposed to construct suitable networks, in which networks are selected based on the predictive stochastic complexity (PSC) criterion, and the selected networks are estimated using both recursive Newton algorithms and the method of nonlinear least squares. Our results show that PSC is a sensible criterion for selecting networks and for certain exchange rate series, some selected network models have significant market timing ability and/or significantly lower out‐of‐sample mean squared prediction error relative to the random walk model.
The use of low‐temperature crystallisation in the determination of component acids of liquid fats. II. Fats which contain linolenic as well as linoleic and oleic acids
Authors: Gunstone F. D. , Hilditch T. P.
Published: July 2007

The mixed fatty acids are first separated into sovorul groups by crystallisation from appropriate solvents at low temperatures. In each group the proportions of linolenic, linoleic, oleiu and saturated acids are determined spectrographically after isomerisation with alkali,1 Palmitic acid and other saturated acids may be determined by fractional distillation of the completely hydrogenated methyl eaters of the total mixed fatty acids, or from direct ester‐fractionation of the methyl esters of each group of the mixed acids obtained by low temperature crystallization. The accuracy of the determination depends largely on the degree to which, by low temperature crystallisations, the mixed fatty acids are resolved into (i) portions rich in olcic and/or saturated acids (with only minor amounts of linoleic and linolenic acid) and (ii) portions rich in linoleic and/or linolenic acid (with relatively small proportions of oleic and saturated acids). The procedure is illustrated by determination of the component acids of linseed oil, of wheat germ oil, and of two specimens of rubber seed oil.

The propects of rubber seed oil as a drying oil for the paint industry are briefly discussed.
Drinking water from sea water by a chemical method
Authors: Akeroyd E. I. , Holmes E. L. , Klein A.
Published: July 2007

Before 1939 the only practical method of converting sea water into drinking water Was by distillation. This method, whilst subjected to improvement during the war, could not be applied for use in the rubber dinghies in which stranded aircrews must exist until they are picked up. For the reason an alternative method was essential and a chemical means of removing the dissolved salts from sea water was developed which was simple in operation and which provided a largo margin of dunking water over that which could be carried in tilts in the emergency packs.

This article describes the development of the process and the results finally achieved. Furthermore, it shows how the properties of ion exchange materials, which in peacetime hud been used mainly for softening hard waters, could be applied to other purposes und assist in the solution of an otherwise difficult chemical problem.
Method for the micro‐determination of the sorption of fumigants
Authors: Wikteringham F. P. W.
Published: July 2007

Brief reference is made to the importance of the study of sorption in investigating problems of fumigation. The application of a two‐chamber sorption apparatus to tie micro‐determination of the torption of chemically reactive fumigants is described is detail. The success of the method depends Inreglv on the precision of the analytical method of determining the concentration of fumigant in the apparatus. For the introduction of known weights of fumigant into the sorption apparatus a sampling procedure has bean employed, which snows advantages over the method of weighing the fumigant out in glass ampoules. The application of the method of reaction in monoethanolamine to the determination of methyl bromide concentrations in the two‐chamber apparatus is described. The analytical errors and the calculation of the average concentration obtaining in the free space of the apparatus during an experiment are discussed.
The solubility of acetylene in acetone
Authors: Brameld V. E. , Clark M. T.
Published: July 2007

Following a brief review of published work on the solubility of acetone, a. new gravimetric method for its determination is described, Results are given for the temperature range 0° to 40° under an acetylene partial pressure of 1 atm. These values are expressed on a weight basis, since such a coefficient is of creator practical value than the more frequently used volume coefficients, ft is demonstrated that the solubility coefficient Sw is related to the temperature by an empirical equation which is sufficiently valid for use over a temperature range of — 30° to 35°. This equal ion is Sw=13100/T‐185.3 where T°K is the temperature and Sw is expressed in mg. of acetylene per gm, of acetone. It is shown that for values of the partial pressure in the region of atmospheric, the solubility is directly proportional to the partial pressure of acetylene in the gas phase above the solution.
The adsorption of aneurin (vitamin B1) on sand
Authors: Ridyard H. N.
Published: July 2007

When using sand as a control column during an investigation of synthetic zeolites it was discovered that the sand itself absorbed aneurin, which could be recovered quantitatively by chit ion with potassium chloride solution. The absorptive capacity of the sand is found to vary with the source, and the evidence suggests that the sand grains possess a zeolitic surface layer due to the action of soil solutions. The grinding of tissues with sand is shown to be likely to cause loss of basic substances present in very low concentration. A quantitative method has been developed which has proved valuable in the estimation of aneurin in wheat products, and possibilities of further simplification and wider application are under examination.
A protective chemical treatment for tinplate
Authors: Kerr R.
Published: July 2007

When tinplate in immersed for 20 sec. At 85° in an alkaline phosphate‐eliminate solution containing n penetrating agent it acquires an invisible film which protects it against blackening by sulphur‐containing foods, and also greatly retards rusting in moist air. An account is given of cannery trials in which the protective film was applied to tinplate cans after filling by adapting the can‐washing machinery, and of a large‐scale experiment in which tinplate sheets were treated by the same process before fabrication into cans, Cans manufactured from treated tinplate combine the advantages of freedom from internal blackening and increased resistance to external rusting, and for a number of packs the amount of tin absorbed by the food during storage is less than in cans made from untreated tinplate.
The structure of clay in relation to road construction
Authors: Blott J. F. T.
Published: July 2007

The chemical coustitution and crystalline structure of clay particles and the physical structure of clay particles and clay suspensions are discussed in relation to the behaviour of sub‐grades and foundations in road construction.
Investigation of the seed oils of some sudan cæsalpinioideæ
Authors: Grindley O. N.
Published: July 2007

The seeds of this sub‐family have a very low content fixed oils, which are highly coloured and contain a high proportion of msaponifiable matter. In moat canon the mixed fatty acids contain about 30% of suturated acids, the balance being a mixture of oleic and linoleie acids, the amounts of the two hitter varying with the species. In all cases, fatty acids of high molecular weight were shown to lie present, a fact that appears to be a characteristic of the entire Legmninoste family.
The determination of tar fog in gas. Part I
Authors: Badger E. H. M. , Wilson D. S.
Published: July 2007

A method for the determination of tar fog in gas is described. Tests made on the removal of tar fog from carburetted water gas in multi‐stage high‐speed exhauster are described and the importance of good cooling of the gas pointed out. Tests made on a coal gas stream containing high‐speed exhausters show that provided there is good cooling in the secondary condensers the tar fog entering the purifiers can be reduced to a very low figure.
The specificity of the saLIcylaldehyde RE. Action for the detection of acetone
Authors: Thomson T.
Published: July 2007

The salicylaldehyde reaction fur the detection of acetone has been studied. It has been shown that the range of specificity hitherto suggested is much too narrow and that the mechanism of the reaction postulated by Braunstein is untenable. A positive salieylaldehyde reaction is given by a wide variety of substances, the essential conditions being condensation of the salieylaldehyde with a reactive methylene group and the formation, through the phenolic hydroxyl group in the salicylaldehyde molecule, of the sodium Bait of the resulting compound. With a relatively concentrated solution of acetone, at any rate, the red colour is due to the formation of the sodium Halt of salieylacetone. Such salts have been isolated and characterised. The reaction is more sensitive for acetone than for any of the other substances examined.
A note on the bromination of p‐nitrotoluene
Authors: Cavill G. W. K.
Published: July 2007

The bromination of p‐nitrotoluene in the presence of antimony tribromide gives p‐nitrobenzyl bromide, the use of ferric bromide as catalyst results in the formation of 2 bromo as nitrotoluene. The former method is suggested as a convenient one for the preparation of p‐nitrobenzyl bromide.
South African fish products. Part XXII. Periodic acid as a reagent in the analysis of the unsaponifiable fractions of natural fats
Authors: Karnovsky M. L. , Rapson W. S.
Published: July 2007

A study of the distribution, nature and metabolism of glyceryl ethers in natural fats is in progress, and as a preliminary to the publication of results, a method which has been used for the quantitative estimation of α‐glyceryl others in the unsaponifiable fractions of natural fats is described. In this method the unsaponifiable matter of the fat is treated in solution in ethyl alcohol or ethyl acetate with an excess of periodic acid solution, and the formaldehyde generated is estimated gravimetrically. The results obtained have been checked by volumetric estimation of the periodic acid consumed in the reaction. In very many cases, as with batyl alcohol itself, agreement has been observed between the results of the two methods. Diserepancies with a number of fats indicate, however, the existence in their unsaponifiable matters of substances other than α‐glyceryl others which are attacked by periodie acid. These cases are under fuller investigation.
Part II. The value and the limitations of highspeed turbo‐exhausters for the removal of tar‐fog from carburetted water‐gas
Authors: Badger E. H. M.
Published: July 2007

The present paper is concerned with a study of the factors which affect the removal of tar fog by high‐speed turbo‐exhausters and the assessment of the conditions under which turbo‐exhausters alone provide adequate tar fog removal from carburetted water gas.
Part III. Removal of tar fog from coal gas
Authors: Badger E. H. M.
Published: July 2007

Similar tests to those described in Part II of this linner were made on a coal gas stream. 200.000 cu. ft. per hr. of coal gas from intermittent vertical chamber ovens were cooled in water tube condensers and then passed through a high‐speed two‐stage turbo‐exhauster. On leaving the exhauster the gas was again cooled in water tube condensers, as is usual in coal gas purification, and then passed through a Livesey tar extractor, rotary ammonia washers and oxide of iron purifiers.
The filtration of subsider muds and the effect of bagacillo as a filter aid
Authors: Coalstad S. E.
Published: July 2007

The filtration plant for treating muds produced in clarification is an important section of the sugar mill, and yet but little published investigation work 1ms appeared to date on this process, having as its object the determination of the best operating conditions. Defecation mud is not a free Jittering material, and it is not easy to wash free of sugars on a rotary or other type of filter, in one filtering operation. For this reason an investigation of the composition of subsider mud and its filtering properties was carried out by the writer in the research Department at Kalamia Mill recently, and the results are given below.
The protective action of lead compounds
Authors: Mayne J. E. O.
Published: July 2007

It has been shown that distilled water may be rendered non‐corrosive by contact with lend powder, litharge and red lead, whilst under the same conditions little or no inhibition was obtained from lead peroxide, lead sulphate, lead chromate, basic lead sulphate, basic lead carbonate, iron oxide and titanium oxide. The inhibition was associated with the passage of lead into solution. Atmospheric carbon dioxide removed the lead from solution by precipitating it as basic lead car be unto. In certain cases, therefore, protection broke down, and the results were not very reproducible. Paints have been prepared from the majority of the pigments mentioned above, by grinding them in a drying oil, and it had been found that so long as the lead pigment was sufficiently basic to form lend soaps it yielded a paint film which was capable of making water non‐corrosive. It was concluded, that inhibition was brought about the soluble lead compounds produced by the hydrolysis of lead soaps, and this was confirmed an examination of the behaviour of a commercial sample of lead linoleate, Tins inhibition was obtained even in the presence of small quantities of electrolytes and atmospheric carbon dioxide. It would seem that the ideal vehicle should contain sufficient acid to ensure adequate soap formation, and should yield a film of maximum water resistance, in order that the soluble inhibitive ingredients may be retained as long as possible. The possible ways in which such a vehicle could be developed are discussed in the paper. The mechanism by which the products of hydrolysis of lead linoleate cause inhibition has been examined, and it is concluded that the soluble lead compounds are adsorbed on the bare metal, and act as anodic adsorption inhibitors. The nature of the adsorbed substance has not been clearly established. The paper contains suggestions for future work.
The morgan method of soil testing. Part IV. Use of the spekker absorptiometer for estimating phosphate
Authors: Tinsley J. , Pizer N. H.
Published: July 2007

A direct, quantitative method of estimating 0 to 8 p.p.m. of phosphorus (as phosphate) in Morgan's universal extracting solution (U.E.S.) is described in which molybdenum‐blue is formed in 13 mm. diameter tubes and measured by means of the Spekker photo‐electric absorptiometer. 1 ml. of phosphate solution is used, 1 ml. of a sodium molybdate‐hydrochloric acid solution and 0.5 ml. of n stannous chloride‐hydrochloric acid solution. The sodium molybdatc reagent contains sufficient hydrochloric acid to offset neutralisation of the acidity of U.E.S. by calcium carbonate in calcareous soils. The molybdenum‐blue is formed rapidly and is stable for 30 minutes. The relationship between Spekker drum readings and p.p.m. P is linear. The method is applicable to U.E.S. extracts of acid or highly calcareous soils: evidence of its suitability for soil extracts will appear in a later papor.
The preparation of an active absorbent of hydrogen sulphide from waste oxide of iron
Authors: Whalley H. K.
Published: July 2007

Impure iron oxide, which is a by‐product in the extraction of alumina from bauxite, is valueless as an absorbent for hydrogen sulphide. Attempts to activate the waste oxide by simple chemical treatments were unsuccessful. Partial reduction in coal gas, followed by oxidation with air, gave three groups of oxides showing high activity, high capacity and rapid revivability. Study of the absorption and reactivation reactions showed that sulphidation occurred in two stages: first, a rapid logarithmic reaction, followed by a slower autocatalytic absorption. If the reaction were stopped on completion of the first stage, and the material then revivified, the resultant oxide showed the second autocatalytic stage. Suggestions for the mechanism of the changes involved are advanced.

The activated oxide was shown to be better than all of a number of commercial absorbents examined, except for bog ore admixed with peat, and even with this high‐grade material the comparison was not too unfavourable.
Am improved “kjeldahl trap” and ammonia‐distillation outfit
Authors: Lovecy A.
Published: July 2007

A new design of apparatus for analyses involving the quantitative distillation of ammonia, e.g., in the Devarda procedure, it described. To remove entrained non‐volatile alkali from the vapour, the latter is passed through water at the boiling‐point in a special scrubber. Strict tests, which have been made by reducing samples of a nitric, acid solution and titrating the resultant asonia with the same nitric solution, have demonstrated the quantitative reliability of the apparatus.
The drying of wheat. IV. Phosphatase activity as an index of heat damage in cereals
Authors: Hutson J. B. , Booth R. G.
Published: July 2007

The baking quality, germination vitality and phosphatase activity of a wheat were examined after heat treatment at moisture contents ranging from 5.5 to 35%. Curves relating the percentage of phosphatase inactivation to temperature of treatment are presented. The correlation between phosphatase inactivation and damage to either vitality or baking quality varies with moisture content and is less than that between vitality and baking quality in the important region above 15% moisture. The detection and uset of an ezyme system of greater heat lability than phosphatase is desirable for the unequivocal diagnosis of mild damage to either vitality or baking quality of wheat.
The analysis of external deposits from boilers. part III. Methods in use at British coal utilisation research association for the analysis of the water‐soluble fraction of external boiler deposits
Authors: Edwards A. H. , Flint D.
Published: July 2007

Methods in use at. B.C.U.R.A. for the analysis of the water‐soluble fraction of boiler deposits arc described. A method is given for the extraction of the water‐soluble fraction of an external boiler deposit. The scheme of analysis outlined separates the solution of the water‐soluble fraction into three parts for determinations of (1) acidity, (2) sulphate and alkalis and (3) silica, mixed oxides, lime and magnesia, methods for which are described.
Photosensitive adsorption of water vapour on wool
Authors: Bright Norman F. H. , Carson Thomas
Published: July 2007

The adsorption of water vapour on wool at atmospheric pressure of air at 5 to 20% relative humidity, has been shown to be influenced by the action of light, the effect of irradiation being to increase the moisture content. The magnitude of the change is of the order of 0·3‐0·5% increase on a moisture content of 5% at 12% relative humidity at 20°. The effect, which has been observed at both 20° and 35°, is rapid and reversible. The phenomenon has not so far been observed with a synthetic vegetable protein fibre.
The bromide content of underground waters. Part I. Determination and occurrence of traces of bromide in water
Authors: Houghton G. U.
Published: July 2007

Practically no quantitative data are available as to the bromide content of water supplies in this country. Methods for the determination of small amounts of bromide in water are discussed; a variation of the D'Ans and Höfer method is described which gives reliable results when 0·05‐2·5 p.p.m. of bromine is present in waters of high organic purity. The method measures total bromine and iodine but it is believed that the iodide content will usually be negligible. The apparent bromide content of a number of underground supplies, chiefly in Southern England, is recorded. A qualitative test for traces of bromate is also described.
The determination of the peroxide values of edible fats and oils: The iodimetric method
Authors: Lea C. H.
Published: July 2007

Factors which influence the determination of peroxide values by the iodimetric method have been investigated. These include dissolved oxygen and moisture in the reagent, time and temperature of reaction, and amount of fat taken. The necessity for adequate de‐aëration of the reagent before admixture with the fat had been demonstrated for this, as previously for the photometric ferrous salt method, but the ratio between the “aërobic” and “anaërobic” values is much smaller for the iodimetric than for the ferrous salt method. Alternative procedures for determination of iodimetric peroxide values are recommended by (a) a “cold” method involving standing at laboratory temperature for one hour, or (b) a rapid “hot” method involving heating at the boiling point of the solvent for two minutes.

The increase in apparent peroxide value observed in earlier iodimetric procedures when the quantity of fat taken for the determination was reduced, has been shown to be due to an increasing error reuniting from further oxidation of the fat by dissolved oxygen during the determination, rather than to a decreasing error due to loss of iodine by re‐absorption. In both the procedures now recommended, exclusion of atmospheric oxygen is adequate and the results, within reasonable limits, are independent of the size of the sample of fat taken.
The estimation of sulphur compounds in crude and refined benzoles. Part II
Authors: Claxton G. , Hoffert W. H.
Published: July 2007

Based on the experiments described in Part I, methods of analysis of sulphur compounds that have been found successful are described in detail, followed by a scheme of analysis for a complete examination of the sulphur compounds in a crude or refined benzole. For the sake of convenience, the methods of analysis are given in the order in which they appear in the complete scheme.