PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
107 
the truth. There are no considerable accidental errors of observation in these experi- 
ments, to judge from their agreement with one another. Of the constants for calcu- 
lating the experiments, x and y must be taken into account in regard to any possible 
uncertainty. It has been assumed that #=0‘615 and ^=0-431 ; if we took #=0*63 
and y=0*41, the specific heat as the mean of four experiments would be =0*30 ; if x 
were 0-67 and y 0*45, the specific heat would be 0*21. But from what has been com- 
municated in § 22 and § 27 in reference to the determination of x and y, it cannot be 
assumed that any possible uncertainty in reference to these values can reach either of 
the above limits. It can be assumed with the greater certainty that the specific heat of 
amorphous boron is between 0*2 and 03 and nearly 0*25, because x and y could not 
simultaneously both be found too great or too small (if x had been too small y would 
have been too great, and vice versd). 
Crystallized Boron *. 
Experiments with Naphtha A. Glass 3. Temperature of the Air 18°*9-18°*7. 
T. 
T'. 
t'. 
t. 
M. 
m. 
/• y- 
X. 
sp. H. 
O 
0 
0 
o 
grms. 
grms. 
gnn. 
grm. 
50*9 
20*8 
20*52 
18*53 
26*94 
2*82 
1*53 0*431 
0*453 
0*237 
51*3 
20*8 
20*52 
18*52 
26*975 
55 
55 55 
55 
0*233 
51*5 
20*8 
20*53 
18*53 
26*985 
n 
55 55 
55 
0*229 
51*4 
20*8 
20*46 
18*43 
26*99 
55 
l*52f „ 
Mean 
55 
0*222 
0*230 
Hence the specific heat of the crystallized (adamantine) boron investigated is 0*230 
between 21° and 51°; it is pretty near that found for amorphous boron, 0*254. Reg- 
nattlt found J (between 98° and 100° and the mean temperature) 0*225 for a specimen of 
crystallized boron prepared by Rousseau; 0*257 for one prepared by Debray; 0*262 
for one obtained from Deville; and 0*235 for a specimen of graphitic boron prepared 
by Debray. The specific heat of amorphous boron could not be determined by Reg- 
nault’s method, because, when heated to 100° in air, it partially oxidizes into boracic acid 
with disengagement of heat (three experiments, in which the quantity of boracic acid 
formed was determined, and its specific heat, but not the thermal action due to the forma- 
tion of hydrated boracic acid in immersion in water allowed for, gave respectively 0*405, 
0*348, and 0*360, which numbers Regnault does not consider as even approximately re- 
presenting the specific heat of amorphous boron), and when greatly cooled disengages a 
quantity of air when immersed in warmer water, which renders the results uncertain. 
* “Made in Paris, probably by Rousseau, and doubtless by melting borax with aluminium. To conclude 
from its external appearance, it probably contained some aluminium and carbon : compare the analysis in 
Ann. der Chem. und Pharm. vol. ci. p. 347.” — Wohlek. 
t After drying tbe stopper. 
+ Ann. de Chim. et de Pbys. [3] vol. lxiii. p. 31. 
