580 
MESSES. GIBSON AND BAECLAY ON MEASUEEMENTS OE 
These readings give the zero value =1572 — 188 = 1384. With this value of z the fol- 
lowing measurements of the cylindrical paraffine condenser were obtained : — 
Date. 
Temperature. 
Condenser Scale. 
Value. 
Outside. 
Inside. 
Mean. 
Ct. 
ec-\-/3 
2 * 
Jan. 6, 1870 
O 
O 
13 
O 
322 
309 
1693 
Jan. 6, 1870 
10 
io-7 
10-35 
316 
303 
1687 
Jan. 6, 1870 
26*2 
13-4 
198 
314 
301 
1685 
Jan. 7, 1870 
21-2 
20-5 
20-85 
318 
305 
1689 
Jan. 8, 1870 
8-2 
8-2 
8-2 
322 
309 
1693 
Jan. 8,1870 
17-7 
14-9 
16-3 
319 
306 
1690 
Jan. 8, 1870 
16-4 
16-2 
16-3 
319 
306 
1690 
Jan. 11, 1870 
7*1 
7-1 
7-1 
320 
307 
1691 
Jan. 12, 1870......... 
24-7 
24 
24-35 
316 
303 
1687 
Jan. 12, 1870 
23 
24-3 
23-65 
317 
304 
1688 
In order to vary the conditions of the experiment so as to allow the paraffine to 
expand more freely, a condenser of the following form was employed. Its metallic 
surfaces consisted of circular pieces of tinfoil. These were arranged horizontally with 
plates of paraffine half a centimetre thick between them. The following Table shows 
the values obtained for this condenser at various temperatures, the zero-value of the 
sliding condenser being still the same : — 
Condenser Scale. 
Date. 
Temp. 
Value. 
a. 
2 * 
Jan. 18, 1870 
O 
11-4 
269 
256 
1640 
Jan. 18, 1870 
21-8 
263 
250 
1634 
Jan. 19, 1870 
14-5 
267 
254 
1638 
Jan. 25, 1870 
7*2 
271 
258 
1642 
These values arranged according to temperature are as follows : — 
Temp. 
Value. 
O 
7'2 
1642 
11-4 
1640 
14-5 
1638 
21-8 
1634 
Some experiments were now made upon the expansion of paraffine with temperature, 
with a view to determine the alterations produced by it in the capacity of paraffine con- 
densers. This was done by weighing a quantity of paraffine in thin plates, with a 
platinum sinker attached, in distilled water at different temperatures. The weight of 
the paraffine in air was 48-358 grammes, that of the platinum was 8-625 grammes, or 
