Prof. TyndalPs Contributions to Molecular Physics. 445 



In these experiments I employed a less delicate galvanometer 

 than that used in my former researches. The experiments were 

 made on the 29th of September, and on the following day I 

 repeated them with the following results : — 



Table II. — Radiation of heat through Liquids. Source of heat, 

 red-hot platinum spiral. Thickness of liquid layer 007 of 

 an inch. 



Name of liquid. 



Iodide of methyle 

 Iodide of ethyle 

 Benzole 



Amylene . . 

 Sulphuric ether 

 Acetic ether 

 Formic ether . 

 Alcohol . . 

 Water . . . 

 Total heat . 



Deflection. 



. 33-5 

 . 35-5 



37-5 



39'5 

 , 41-0 

 . 41-5 



42-4 



43-5 



44-7 



46-7 



Absorption per 100. 



53-7 

 58-7 

 64-4 

 70-7 

 75-4 

 76-9 

 80-0 

 84-2 

 90-5 

 100-0 



On the 28th of October my most delicate galvanometer was at 

 liberty, and with it I executed the experiments performed with 

 the coarser one. The following are the results : — 



Table III. — Radiation of heat through Liquids. Source, red- 

 hot platinum spiral. Thickuess of liquid layer 0*07 of an inch. 



Name of liquid. Deflection. Absorption 



per 100. 



Bisulphide of carbon 9*0 12*5 



Chloroform 25*2 35-0 



Iodide of methyle 36'0 532 54*3 



Ditto, strongly coloured with iodine . 36*0 53*2 



Iodide of ethyle 38-2 59*0 59'6 



Benzole 39'2 62*5 65-7 



Amylene 42'0 73'6 72-3 



Sulphuric ether 42*6 76*1 77'4 



Acetic ether 434 78*0 79*3 



Formic ether 43*3 790 80'0 



Alcohol 44-4 83-6 85*4 



Water 45*6 88'8 90*9 



Total heat 48-0 1000 



I have here placed beside the results obtained with the deli- 

 cate galvanometer, the means of those obtained with the coarser 

 one. It is not my object to push these measurements to the last 



