218 Scientific Intelligence. 
large number of experiments they deduced the following results, 
The specific volume of solid phosphorus is given by the equation: 
Wj=W 4g +2000 K 10774 +1150 K 1071974? 
and of liquid phosphorus by : 
W j=, - +2969 X 1077 (£—50) +2115 & 1071 9(— 50)? 
The mean co-efficient of dilatation per degree for solid phos- 
phorus from 0° to v° is given by the formula 
R=3674 X 1077-211 K 107 %¢, 
and for liquid phosphorus: 
=5167X 10-7 +4370 X 10-9(t—50). 
— Gazz. Chim. TItal., iv, 1874. ” oF 
11. Velocity of Light.—M. Cornu gives the results of some 
measurements he has made on the velocity of light under the 
direction of the Council of the Observatory, at the suggestion 
of LeVerrier and Fizeau. The method employed was that of the 
toothed-wheel, first employed by Fizeau in 1849. The result then 
obtained was 298,500 meters from measurements between the 
Polytechnic School and Mt. Valérian. The stations now selected 
M 
a chronograph and electric register the time measured to thou- 
sandths of a second. e method of measurement is well known, 
ber of times the observation was made, and the column V gives 
the corresponding velocity. The mean of the whole, giving 
n ™m Vv n m Vv 
4 15 300,130 13 4 300,340 
5 33 300,530 14 9 300,350 
6 20 300,750 15 65 300,290 
7 10 300,820 16 4 300,620 
8 7 299,940 17 22 300,000 
9 94 300,550 18 35 300,150 
10 69 300,640 19 6 299,550 
11 72 300,350 200 — —— 
12 3 300,500 21 36 300,060 
proper weights to each, is 300,330 in air, or 300,400 meters 1 
vacuo, with a probable error of only one-tenth of one per cent. 
