227 



Discurso lido em 13 de Maio de 1838 iia Sessas publica da Acade- 

 mia Real das Sciencias de Lisbua, par Joaquim Jose Da Costa 

 de Macedo — By the Academy. 



Astronomische Nachrichten, Nos. 349 to 354. — By Professor Schu- 

 macher. 



Memoires de I'Academie Imperiale des Sciences de St Petersbourg. 

 (Sciences Mathematiques, &c.) Tome i. livrs. 5, 6; et tome ii. 

 livrs. 1, 2. 



Do. do. (Sciences Naturelles). Tome ii. livrs. 4, 5, 6. 



Do. do. (Memoires presentes par divers Savans). Tome iii. 

 livrs. 3, 4, 5, 6 ; et tome iv. livrs. 1, 2. 



Recueil des Actes de la Seance Publique de I'Academie Imperiale 

 des Sciences de St Petersbourg tenue le 29 Decembre 1837. 

 — By the Academy. 



Comptes Rendus Hebdomadaires des Seances de TAcademie des 

 Sciences, 1838. (2™« Semestre). Nos. 21, 22 By the Aca- 

 demy. 



Natuur-en-Scheikundig Arcbief, uitgegeven door G. J. Mulder en 

 W. Wenckebacli. Jaargang 1837. 3d Stuk By the Edi- 

 tors. 



The following Communications were read : 

 1. On the Law which connects the Elastic Force of Vapour 

 with its Temperature. By John Scott Russell, Esq. 



The object of the paper was to examine into the present state 

 of our knowledge of this subject, for the purpose of ascertaining its 

 defects, and indicating the manner in which they were to be re- 

 medied. 



Although it appears to any one who examines only a single 

 authority on the constitution of vapour, that its laws are sufficient- 

 ly definite, yet on comparing together all the authorities we pos- 

 sess on this subject, or even the best of them, we find such dis- 

 crepancies both in the general expressions of the law, and in the 

 experiments themselves upon which they rest, as are highly dis- 

 creditable to mechanical science, and far exceed the limits of error 

 usually admitted in similar departments of experimental science. 

 Between 32° and 212°, the difference between Dr Dalton's expe- 

 riments and Dr Ure's amounts to more than three-tenths of an inch 

 of mercury. Between the experiments of the Institute of France 

 and of the Franklin Institute, — the latest and most extensive series 

 of experiments,— there is a difference at the eleventh atmosphere 



