440 [Feb. 26, 



to the metallic state ; its power of forming a strongly acid oxide ; 

 and, according to Dr. Miller, the complexity of its photographic 

 spectrum, all prove that thallium cannot consistently be classed 

 anywhere but amongst the heavy metals, mercury, silver, lead, &c. 

 No weight is attached to M. Dumas's argument in favour of thallium 

 being related to potassium and sodium because its equivalent is 

 rather near a figure obtained by adding twice the atomic weight 

 of one metal to four times the atomic weight of the other. The 

 author shows that, by similar processes of addition, multiplication, 

 or subtraction, it is not difficult to prove that thallium is related 

 to any desired group of elements. 



The author gives full analytical notes on thallium, showing where 

 it would occur in the ordinary course of analysis, and detailing 

 accurate methods of separating it from every metal with which it 

 can be accompanied. 



February 26, 1863. 



Major-General SABINE, President, in the Chair. 

 The following communications were read : 



I. "On the Effect of Temperature on the Secretion of Urea, 

 as observed on a Voyage to China, and at Hong Kong." 

 By EMIL BECHEE, M.D., Assistant-Surgeon, Army Medical 

 Staff. Communicated by Dr. EDMUND A. PARKES. Re- 

 ceived January 20, 1863. 



(Abstract.) 



With a view to extend our knowledge of the physiological effects 

 of temperature, with especial regard to the influence of tropical 

 heat on the healthy system, Dr. Becher, with the liberal assistance 

 of the Director- General, Army Medical Department, took advantage 

 of a voyage to China (round the Cape of Good Hope) in 1857, and 

 a short residence at Hong Kong, in order to determine on himself 

 the influence of the extreme variations of temperature incidental to 

 that voyage, on the quantity of urine, urea, and chloride of sodium 

 excreted during each twenty-four hours. 



