REVIEWS The object of lhis department of theJournal is to issue, as promptly as jdssiblc critical digests of allJourna2 articles that bear upon any phase ofPhyszca1 Chemistry General The deduction of the absolute temperature from the normal thermometer. Comptes rendus, 136, 809 (1903). -I t is customary to take th,e ab-H. Pellat. solute temperature as I T=-+ t . The author deduces the formula dUT where K is the variation from the ideal gas, -, tion K/a equals + 0.11". On the spontaneous

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... n of heat from radium salts. P. Curie and A. Ladorde. Comptes rendus, 136, 673 (1903). -By means of a thermocouple it was shown that a gram of barium chloride contaiiiing about one-sixth of its weight of radium chloride was continuously 1.5" hotter than a gram of pure barium chloride kept under apparently similar conditions. The approximate calculation is made that one gram of radium would evolve about roo cal per hour or one combining weight (225 g) about 2 2 ; 5 0 0 cals per hour, an amount comparable with the heat of conibustion of one combining weight of hydrogen burning in oxygen. Heats of combustion of organic compounds considered as additive properties. P, Lemoult. Comptes rendus, 136, 895 ('903). -The author proposes to test for hydrocarbons the accuracy of the formula Q=157n+A. I n this formula Q is the molecular heat of combustion, n is the number of carbon atoms in the formula, and A is a constant which varies for each homologous series. In fifty-three cases out of sixty, the formula agrees with the facts to within less than one percent. Heats of combustion of organic compounds considered as additive properties. P. Lemodt. Comptes rendus, 137,515 (1903).-I t is assumed that the heat of combustion of the primary and secondary alcohols C,H"+,OH can be represented by the equation Q = 15712 + IO. This forniula was applied to eight alcohols and stood the test well. Other modifications of the same general formula are used for testing alcohols, for ethers, for aldehydes and ketones. For hydrogen, the correcw. Reviews 295 On the heat of combustion of phosphorus and OD the phosphoric anhydrides. H. Giran. Comptes rendus, 136, 550 (r903). -The heat of combustion of solid white phosphorus is 369.4 cal. The crystallized phosphoric anhydride evolves the most heat on dissolving in much water, and the vitreous form evolves the least, the amorphous form coming in between the other two. The heat effects confirm the analytical data that phosphorus pentoxide dissolves first as metaphosphoric acid. Heat of neutralization of hydroferrocyanic acid. P. Chrktien and]. Guinchant. Comptes rendus, 137, 65 (~9 0 3 ) . -The authors have determined the heat of neutralization of hydroferrocyanic acid ( 4 X 14.47 cal at 1 2~) and the heats evolved when this substance combines with ether or acetone. I t was not possible to calculate these last heat effects from the dissociation pressure curves because the presence of water vapor as catalytic agent introduced difficulties. Heats of formation of some nitrogen and sulphur compounds. M. Delkjine. W. D. B. Heat of formation of some barium compounds. A . Guntz. Comptes ren- w. D. B. A new apparatus for preparing gases pure. H. Moissan. Comptes rendus, 137,363 (r903). -The abjections to fused calcium chloride, pumice stone soaked in sulphuric acid, etc., are that air is always present, that secondary reactions are liable to take place, and that there is always difficulty with joints and stoppers. The author therefore dries gases by cooling them to -50'. To purify them he solidifies them and then separates the impurities by fractional distillation. w. D. 6. An electrical thermostat. C. Marig and R. Marquis. Comptes rendus, 136, 614 (1903). -The bath is heated by a current passing through a platinum wire. A mercury and acetone thermoregulator closes and opens a secondary circuit which regulates the heating by means of a relay. A quartz-glass mercury-arc lamp. M. Bodenstein. Zeit. Elektrochemie, IO, rz3 (1904). -Heraeus has now placed on the market an Arons lamp made of quartz instead of glass. This can be used as a source of ultra-violet light.