Proceedings of Learned Societies, 385 



dependent and singularly simple process, altogether preparatory 

 to the actual evolution of the roots themselves. So simple and so 

 satisfactory is the method of Sturm, that it must entirely supersede 

 all former investigations on this subject, and it will henceforth oc- 

 cupy the same distinction in the theory of equations that Taylor's 

 theorem does in the differential calculus. The present translation, 

 from a large and expensive volume not readily accessible in this 

 country, cannot fail to be acceptable to all classes of readers inter- 

 ested in the progress of mathematical science. It seems to have 

 been executed with great care and fidelity, and is, indeed, superior 

 to the original in one important particular — typographical accu- 

 racy; since, upon a careful comparison of the two, we find that se- 

 veral errors in the original have been corrected in the translation. 

 The work is printed in a manner worthy of the subject. * # * 



L. Proceedings of Learned Societies, 



OFFICIAL REPORT OF THE PROCEEDINGS OF THE BRITISH AS- 

 SOCIATION FOR THE ADVANCEMENT OF SCIENCE, AT THE 

 DUBLIN MEETING, AUGUST 1835. 



Communicated by the Council and Secretaries. 



[Continued from p. 315.] 



Notices and Abstracts of Miscellaneous Communications to the Sections, 



continued. 



CHEMISTRY. — ELECTRICITY. 



On the Specific Heats of the permanently elastic Fluids. By 



James Apjohn, M.D., Professor of Chemistry in the Royal Col- 



lege of Surgeons, Ireland, 



After an introductory view of the state of knowledge on this sub- 

 ject, Dr. Apjohn proceeded to explain the principle of an entirely 

 new method which he was enabled to apply to the investigation of 

 the difficult problem under consideration, in consequence of having 

 been recently fortunate enough to arrive at a formula which ex- 

 presses, with extreme and unexpected precision, the relation exist- 

 ing between the indications of a wet-bulb thermometer and the cor- 

 responding dew-points. This formula* (see Proceedings of Ma- 

 thematical and Physical Section, p. 3 IS,) being equally true of all 

 gases, obviously suggests a method of comparing their specific 

 heats. For as in the case of every gas it may be deduced that 



a— \L ""** ) e x'— , it is clear that if we determine values of/',/" 

 48 d p 



• f'^zf— 48 a - X Z-, in which /" is the elastic force of vapour at the 



dew-point; /' its elastic force at the temperature t', shown by the wet ther" 

 mometer ; d the difference between the latter temperature, and t that of the 

 air; a the specific heat of air; and e the caloric of elasticity of the vapour 

 of water whose elastic force or tension is represented by/'. 

 Third Series, Vol. 7. No. 41. Nov. 1835. 3 D 



