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After a brief description of a new apparatus for the determination of heats of combustion, the theory of an isothermally jacketed calorimeter is discussed. Several factors which require attention in accurate determinations are dealt with, viz.: purity of reagents, completeness of the combustion reaction, determination of time, determination of weight and corrections of the second order. A description is then given of some details of the apparatus and method. The accuracy attained, 0.01-0.02%, is demonstrated in a series of experiments. Finally, it is shown that the heat of combusiton of our sample of benzoic acid is in excellent agreement with that of preparation 39b of the National Bureau of Standards, Washington.

In a previous communication 1 ), the hydrolysis of cis- and trans-1:4-cyclohexane-di-tritylether with hydrochloric acid in water and propanone. is described. In order to confirm the results obtained in that paper, a method has been worked out, by which these ethers are quantitatively decomposed by treatment with dry hydrogen chloride in anhydrous benzene or chloroform solution. The diols separate as hydrogen chloride addition compounds (with benzene of crystallisation), which dissociate completely in the solid state. The 1:4-cyclohexanediol preparations obtained by both these methods, were absolutely identical. There appears to be no conversion of cis trans or vice versa in these reactions. The cis-diol is converted at 101°. 4 into a liquid crystalline phase, melting at 113°.0. The first process requires about four times as much heat as the second.

From this investigation it is concluded that expansine C7H6O4, a substance with bactericidal and fungicidal properties isolated by Oosterhuis and Luyken 1 ) from the culture liquid of Penicillium expansum Westl., very probably has the structure of an anhydro-3-hydroxymethylene-tetrahydro-γ-pyron-2-carboxylic acid. Expansine is probably identical with patulin 1 ), claviformin 2 ) and clavacin 3 ).

Au cours de la separation des cyclohexane-1,3-diols obtenus par reduction catalytique du resorcinol par la voie des ethers ditrityliques, il s'est produit des complications que Lindemann et Baumann n'ont pas decrites. Le perfectionnement du procede mena au diol-cis a point de fusion de 83°, l'isomere trans fondant a 117°. La meme methode, appliquee au melange de diols obtenu par hydrogenation du quinol sans dissolvant, fournit les deux cyclohexane-1,4-diols isomeres a un etat tres pur. Il fut constate que les isomeres fondaient respectivement a 112 et 143°. Pour l'analyse thermique furent determinees les courbes de fusion des systemes 1,4-diol cis et trans, 1,4-diol-ditritylether cis et trans, et 1,4-diol-diacetate cis et trans du cyclohexane. Ces diagrammes ont montre que le compose a point de fusion de 100-102° prepare selon von Baeyer, lequel jusqu'ici passait pour le cyclohexane-1,4-diol-cis a l'etat pur, est en realite un melange d'environ 84% de cis- et de 16% de trans-1,4-diol. De meme le diacetate du cyclohexane-1,4-diol-cis de von Bayer contenait 17% de l'isomere trans.

The heats of combustions of all the phenylethenes except styrene 1 ), were measured. The values (UR) given in the table below refer to the isothermisochore reaction: CmHn + (m + 1/4 n) O2 m CO2(g) + 1/2 n H2O(l) at 30 atm O2 and 25° C.

A method is described for filling thin-walled ampullae with volatile liquids with the total exclusion of air and water. In this way it is possible to weigh out accurately the amount of material used for a heat of combustion measurement before the experiment is made. To aid the combustion reaction in proceeding to completion a high platinum crucible is used covered with a platinum shield. In a normal heat of combustion reaction it is impossible to detect the presence of carbon monoxide in the combustion gases. The reproducibility obtained is 0.01-0.02%.