714 



SCIENCE. 



[N. S. Vol. XIX. No.< 



ciety, on the other hand, is devoted not 

 merely to the sciences, but to the humani- 

 ties and literature as well. It has been 

 objected that such an ambitious program 

 belongs rather to the eighteenth century 

 'than to the twentieth, and certainly the 

 numerous technical societies which have 

 arisen in relatively recent years bear wit- 

 ness to the increasing tendency to special- 

 ization in all fields of learning. It does 

 not, however, follow that the growth of 

 these technical societies has supplanted the 

 need of more general ones. It is of course 

 desirable that the papers presented at the 

 meetings of the American Philosophical 

 Society should be of broad and general 

 interest, and such they generally are. 



These general meetings afford the op- 

 portunity of hearing and discussing re- 

 cent advances in various subjects and also 

 of meeting and becoming acquainted with 

 eminent authorities in those fields ; to many 

 persons these have seemed to be attractions 

 of no small order. 



The meeting of the society was held this 

 year on April 7, 8 and 9, in the historic 

 home of the society on Independence 

 Square, Philadelphia, where regular meet- 

 ings have been held for about one hundred 

 and twenty years. The meeting was called 

 to order on Thursday morning with a brief 

 address of welcome by the president, Pro- 

 fessor Edgar F. Smith, after which the fol- 

 lowing papers were presented in the order 

 named : 



The Role of Carbon: Professor Albert B. 



Prescott, Ann Arbor, Mich. 



The central position of the element car- 

 bon among the others as shown in the 

 periodic system, together with its innate 

 character, preeminent rather than excep- 

 tional in comparison, together give its 

 capacity for combination. Through stud- 

 ies of carbon eompovinds chemistry at large 

 has been enriched by facts of molecular 



constitution, correlated with all physical 

 constants. When the nature of the living 

 proteids shall become known molecular 

 constitution will be included in that knowl- 

 edge, and the atom of carbon or its theoret- 

 ical equivalent will have its part in the 

 discoveries then made. 



Dimethyl Racemic Acid, its Synthesis and 

 Derivatives: Professor H. F. Keller, 

 Philadelphia. 



The subject of this paper is an experi- 

 mental study of a crystallized acid which 

 had first been obtained, in very small quan- 

 tities, by Professor Fitting and the author 

 in an investigation upon diacetyl, an im- 

 portant compound of carbon discovered by 

 them. The present paper describes the 

 synthetic preparation of the acid on a 

 larger scale, and by an improved method, 

 and supplies more complete data concern- 

 ing its physical and chemical characters. 

 It records the preparation of a number of 

 new salts and many analytical results, con- 

 firming the deductions which had been 

 drawn from scanty observations in the orig- 

 inal research. 



Sources of Error in the Determination of 

 the Atomic Weight of Nitrogen: Theo- 

 dore W. Richards, Cambridge, Mass. 

 On comparing Stas's and Scott's anal- 

 yses of ammonic bromide, it is shown that 

 while Stas probably failed to purify am- 

 monia with siifficient care, Scott, although 

 working with purer ammonia, used bro- 

 mine which was less pure. Thus Stas's 

 results would yield too high an atomic 

 weight of nitrogen, and Scott's one too low. 

 The study of the other available data, in- 

 cluding the results of Ramsay and Aston 

 and some preliminary Harvard work, seems 

 to show that the assumption of inconstancy 

 in the atomic weights is not demanded by 

 the facts, and that the atomic weight of 

 nitrogen is between 14.02 and 14.04. 



