284 



SCIENCE. 



[N. S. Vol. XVI. 2s^o 399. 



These and other aspects of the question 

 will receive consideration in the more com- 

 plete paper soon to be published in the 

 Proceedings of the American Academy and 

 the Zeitschrift fiir ijhysikalische Chemie. 



The Exactness of Faraday's Law: T. W. 



Richards. 



After reviewing work done in cooperation 

 with E. Collins and G. W. Heimrod (which 

 showed that Faraday 's law holds with great 

 accuracy for aqueous solutions and ordi- 

 nary temperatures), the speaker described 

 some more recent work done with the assist- 

 ance of W. N. StuU. The weight of silver 

 deposited in the 'porous cup voltameter' of 

 Richards and Heimrod was compared with 

 the weight deposited by the same current 

 from a solution of argentic nitrate in fused 

 sodie and potassic nitrates at 300°. After 

 taking several precautions which cannot be 

 described here, and subtracting the weights 

 of alkaline nitrates included in the silver 

 crystals, it was found that the weights were 

 identical within the limits of error of the 

 experiment (about 0.005 per cent.). This 

 investigation places Faraday's law among 

 the most exact and invariable of the laws 

 of nature. 



The Electrical Conductivity and Freezing 

 Points of Aqueous Solutions of Certain 

 Metallic Salts of Tartaric, Malic and 

 Succinic Acids: 0. F. Tower. 

 In an article about two years ago it was 

 shown that the molecular conductivity of 

 aqueous solutions of the tartrates of nickel 

 and cobalt was very low, and also that the 

 freezing point lowerings yielded molecular 

 weights greater than those calculated from 

 the simple formulas. These results have 

 been confirmed and similar determinations 

 made with the tartrates of magnesium, 

 barium and manganese, and the malates 

 and succinates of nickel, cobalt and mag- 

 nesium. The results show that magnesium 

 tartrate acts, as it may be termed, normally. 



The tartrates of barium and manganese 

 give results but little different from those of 

 magnesiiun tartrate. Nickel and cobalt 

 malates yield results considerably different 

 from those of magnesium malate, but the 

 diiJereuce is not so great as between the tar- 

 trates of the same metals. The succinates 

 of nickel and cobalt act not greatly differ- 

 ent from magnesium succinate. The ma- 

 lates and tartrates of nickel and cobalt seem 

 to be polymerized in aqueous solution, the 

 malates, however, less so than the tartrates. 

 The polymerizing influence is dependent on 

 the presence of an hydroxyl grouj) in the 

 acid radicle, and this influence is stronger 

 the greater the number of these groups 

 present. 



A Thermochemical Constant: F. W. 



Clarke. 



The author has studied the heats of com- 

 bustion of organic compounds, as deter- 

 mined by Thomsen. These data represent 

 substances burned as gas, with production 

 of gaseous carbon dioxide and liquid water. 

 By a simple correction applied to the last- 

 named factor all the equations of com- 

 bustion may be reduced to the gaseous form 

 throughout, under uniform conditions of 

 temperature and pressure. So adjusted, by 

 ai^plication of a definite formula, nearly 

 every equation yields a constant which is 

 identical in value with the neutralization 

 constant of strong acids and gases. The 

 average, in 66 cases, is 13,773 small calories. 

 From this constant, and the original equa- 

 tions, the conclusion is reached that the 

 absolute heat of formation, from gaseous, 

 dissociated atoms, of the aliphatic hydro- 

 carbons and their simpler derivatives, is 

 proportional to the number of atomic link- 

 ings within the molecule. In this calcula- 

 tion every linking counts as one, and single, 

 double or triple unions between carbon 

 atoms become identical as regards their 

 thermal value. The conclusion is re'volu- 



