104 
PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
should have liked to include a still larger number of bodies in my investigations ; but 
a limit was put by the straining of the eyes from constant reading of finely divided 
scales, and by the injurious action which the long-continued working with coal-tar 
naphtha produces. 
My crystallographic collection furnished me with much material for investigating the 
specific heat of both naturally occurring and artificially prepared substances, but for 
much more I have to thank others. By far the greater part of the chemical prepara- 
tions investigated ! obtained from the Laboratory of the University of Giessen, through 
the kindness of the Director, Professor Will, and of the assistants, Professor Engelbach, 
to whom my thanks are especially due, Drs. Korner and Dehn. Professor Wohler, of 
Gottingen, placed a number of chemical preparations at my disposal. Professor 
Bunsen, of Heidelberg, has helped me to the investigation of some rubidium-com- 
pounds. Platinum and iridium I have been furnished with by M. Her^eus, the pro- 
prietor of the well-known platinum-manufactory in Hanau. I have had a very large 
number of minerals from the mineral collection of the University of Giessen, 
through the kindness of the Director, Professor Knop; and to obtain the necessary 
quantity of dioptase, Professors Blum of Heidelberg, and Dunker of Marburg, have 
contributed. 
32. The signification of the letters in the statement of the following experiments 
and their calculation is clear from § 17 ; in reference to the value of the numbers for 
M, compare § 21, for x § 22, for T' § 23, for y § 27 and § 30. 
It would require too much space always to give the comparison of my results with 
those of other observers. I can only do this in individual cases where there are con- 
siderable differences and their discussion is of importance. For other substances, where 
there are recent observations by trustworthy observers, the Tables in § 82 to § 89 give 
data for comparison. 
33. Sulphur: pieces of transparent (rhombic) crystals from Girgenti. I made three 
series of experiments with this substance. 
I.— 
Experiments with Water. Glass 1. 
Temperature of the Air 13°-2. 
T. 
O 
T'. 
O 
t'. 
o 
t. 
M. 
grms. 
m. 
grms. 
/• 
grm. 
y* 
sc. 
grm. 
sp. H. 
45-8 
15-5 
15-24 
11-74 
26-95 
4-16 
1-765 
1-000 
0-651 
0-168 
46*0 
16-2 
15-93 
12-52 
26-935 
55 
55 
55 
55 
0-160 
45-2 
16-0 
15-73 
12-42 
26-945 
55 
55 
55 
0-153 
45-8 
16-4 
16-05 
12-74 
26-96 
55 
1-75* 
55 
Mean 
55 
0-153 
0-159 
* After drying the stopper : compare § 25. 
