DR. T. S. HUMPIDGE OR THE ATOMIC WEIGHT OP GLUCINUM. 
611 
now introduced, the calorimeter returned to its original position, the agitator worked 
a few times and a reading made at the end of the half minute. Renewed agitations 
„ . . ° 
and readings are then made for every half minute until the maximum temperature (0) 
! is reached. The time to reach this maximum for metallic substances, with which I 
have as yet only experimented, is about a half to one minute. 
Although it is not intended to use the calorimeter with water, as the temperature 
difference would be too small for the small quantities employed, three experiments 
were made with pure silver, and two with commercial aluminium (re-fused under 
sodium chloride) to test the apparatus. The following results were obtained, in which 
T, t and 0 have the meanings given above, t' is the temperature of the air, W the 
weight of water, together with the water equivalent of the calorimeter, agitator and 
thermometer (2'91 grammes), w the weight of the substance employed, and s the 
required specific heat. 
Silver in water. 
I. W = 84-25, 
II. W = 84-03, 
w— HP205, 
w— 10-205, 
T=101°*9, £=ll o, 09, 
W(*-<) n . nrp ^ 
< f ^- 0 05677 - 
T=10L°-9, *=ll°-08, 
0=1I°71, t'= 10 o, 9. 
0=ll°-69, t' = 10°-7. 
s= 0-05568. 
III. W = 84*01, w=10*205, T=101°*9, ^ = 10 o> 86, 0=11 O *47, *'=10°-4. 
s=0-05553. 
Mean specific heat = 0‘05600; mean error = 0'0003 = Ob per cent. 
Aluminium in water A 
I. W=85-71, w— 3-502, T=98 0< 6, t— 7 0> 59, 0=8°’42 ; T=8 o> 0. 
s=0-2253. 
II. W = 85-25, w= 3-502, T = 98 0> 5, £ = 8°’56, 0=9°‘37, t'= 8°-5. 
s=0-2212. 
Mean specific heat = 0’2232; mean error = 0’002 = 1 per cent. 
It will thus be evident that results comparable in accuracy with the best determi¬ 
nations can be obtained with the apparatus, and, I need not add, working entirely 
without assistance. I intend shortly to make a series of more extended experiments, 
* Using a wider exit tube, 
