42 Miss Marshall and Dr. Eamsay on the Heats of 



6. First Series of Experiments. March 1894. 



Two lamps were now made with spirals of fine platinum 

 wire in place of carbon filaments. These platinums were each 

 18 inches long, and coiled into spirals with all possible care 

 to prevent neighbouring turns from touching and short- 

 circuiting. The resistances of the platinums were determined 

 by the Wheatstone-bridge method. The coefficient of increase 

 of resistance of platinum with rise of temperature being 

 (approximately) known, the resistance of each spiral for any 

 given temperature could be calculated. It was assumed that 

 the temperature of the spiral was the same as that of the 

 liquid boiling round it. 



A comparison of chlorobenzene and alcohol may serve for 

 an example : — 



Date. 



B. 



Weight evaporated. 



R r 



R a . 



Corrected Weights. 



Ratio =r*' 



L r 



6 H 5 01. 



2 H 8 OH. 



C 6 H 6 C1. 



C 2 H 5 OH. 



March 15. 

 April 20. 



746-3 

 763-0 



145830 

 16-6645 



4-7975 

 5-4195 



4-89 



4-87 



4-27 

 4-31 



14-5830 

 166645 



5-5252 

 61236 



0364 

 0-367 



76-1 



Table II. 



Substance. 



Date. 



B. 



Eatio. 



L. 



Alcohol referred to f 

 water* \ 



May 1 

 „ 4 



767 

 755 



0-387 

 0-388 



208-1 



CS 2 



Mar. 11 

 May 10 

 „ 15 

 „ 16 

 „ 17 

 „ 30 

 June 4 

 ,, 5 

 „ 6 

 „ 7 

 „ 11 

 „ 12 



741-9 

 754-4 



756-8 

 757-7 

 752-7 

 752-3 

 7539 

 754-4 

 753-8 

 755-2 

 754-1 

 758-3 



0-405 

 0-475 

 0-472 

 0-472 

 0-396 

 0-397 

 0-396 

 0-409 

 0-409 

 0-514 

 0-511 

 0-389 



85-0 

 98-6 



82-5 



85-1 



106-7 



81-0 



Acetic Acid 



" " 



Ether 





" 



Ethyl Acetate 



>> »i 



Methyl Formate 



ji »> 



Methyl Butyrate 



* The other substances are referred to Alcohol. 



