304 Scientific Intelligence, 



results so that they represent the formation of gaseous instead of 

 liquid water. He then finds for the aliphatic hydrocarbons and 



their non-oxygenated derivatives that is a con- 



stant, where K represents the heat of combustion of the com- 

 pound, a the number of molecules of CO^ produced, h the num- 

 ber of molecules of H^O, c the number of oxj^gen molecules 

 involved, and n the number of atomic unions or linkings in the 

 compound bui'ned. In fixing the value of n^ double and triple 

 linkings are not distinguished from simple ones, so that for all 

 chain molecules n is equivalent to the number of atoms minus 

 one. The coefiicients 4, 12, 6, 1 and 8 appear to have been 

 chosen arbitrarily, but the results obtained with them in the 

 cases of fourteen hydrocarbons are remarkably uniform, and the 

 author evidently considers it important that the constant, which 

 averages ISj^YS in this case, is very near the neutralization con- 

 stant of acids and bases, which is 13,700 calories. The same 

 uniform constant was obtained with many other organic com- 

 pounds by modifying the formula in accordance with the presence 

 of several other elements : thus for halogen compounds were used 



the formulas — , and 



12a + 6^ -f /i — c — 8?i 1 2a -\- 65 + 2A^ — c— 8/i 



--. — -, -—. where A, A, and A, represent the numbers 



12a + 65-l-4A^ — c — 8;i' ' ' =* ^ 



of chlorine, bromine and iodine molecules, supposed by the author 

 to be formed by the complete combustion of the halides. For 

 nitrogen compounds two formulas were used ; for cyanides and 

 nitrites, where m represents the number of nitrogen molecules 

 set free, the divisor is 12a + 66-}-3m— c — 8m, while for amines 3m 

 is replaced by 9m. For sulphur compounds the term 95 is intro- 

 duced, while Cj, the number of oxygen molecules present in the 

 compound, is subtracted when the latter element is present. In 

 this way conformable results were obtained with nineteen halogen 

 compounds, four cyanides, ten amines, eight sulphur compounds, 

 and eleven alcohols. The ring compounds have not yet been 

 worked out in this way, and there are a few substances in most 

 of the groups which fail to give the usual result. A considera- 

 tion of the exceptions is deferred until the complete memoir is 

 published. The conclusion is reached that, in any class of com- 

 pounds, the heat of formation is proportional to the number of 

 atomic linkings within the molecule, and seems to bear no rela- 

 tion to the masses of the atoms which are combined. 



It is to be hoped that Professor Clarke has discovered a new 

 and important thermochemical law, but from the arbitrary nature 

 of the formulas used the suspicion arises that the law may be a 

 very obscure one. — Jour. Amer. Chem. Soc, xxiv, 882. h. l. w. 



3. The Meatless Condition of Matter. — In the June number of 

 this Journal mention was made of Brinkw^orth and Martin's 

 theory that pressure may be able to prevent moleeular vibration 



