460 Royal Society :— 
when placed side by side, could not be distinguished from one 
another. 
The ova were of the same colour when first deposited, and under- 
went the same changes of appearance, at the same time, in the dark 
and in the light. é 
So far, therefore, as the direct agency of light is concerned in the 
development, growth, nutrition, and coloration of animals, the results 
of these experiments closely correspond with those already recorded 
in my Paper. 
“Supplement to a Paper ‘On the Thermodynamic Theory of 
Steam-engines with dry Saturated Steam, and its application to prac- 
tice.’ By W. J. Macquorn Rankine, C.E., F.R.S. &c.* 
This supplement gives the dimensions, tonnage, indicated horse- 
power, speed, and consumption of fuel, of the steam-ships whose 
engines were the™ subjects of the experiments referred to in the 
original paper. Results are arrived at respecting the available heat 
of combustion of the coal employed, and the efficiency of the furnaces 
and boilers, of which the following is a summary :— 
Available heat of 
Total heat of com- {combustion of 1 lb.) Available 
bustion of 1 Ib. of | of coal in ft.-lbs. |heaé, total 
No. of Kind of boiler, coal in ft.-Ibs., computed from heat, =effi- 
experiment. estimated from | efficiency of steam | ciency of 
chemical compo- and weight of furnace 
sition. coal burned per jand boiler. 
I. Improved Marine 10,000,000 5,420,000 0°542 
Boilers of ordi- 
III, nary proportions. 10,000,000 5,200,000 0°53 
Boiler chiefly com- 
posed of small 
Il vertical water- 
: tubes, with very 
great heating 
surface. 
11,560,000 10,110,000 0°88 
~ Available Heat of Combustion of 1 Ib. of coal 
1,980,000 ft.-Ibs. 
~ Efficiency of steam x Ib. coal per I. H. P. per hour’ 
“Researches on the Phosphorus-Bases.’”’—No. VII. Triphospho- 
nium-compounds. By A. W. Hofmann, LL.D., F.R.S. &c. 
In several previous communications I have submitted to the Royal 
Society the results which I have obtained in examining the deport- 
ment of triethylphosphine with dibromide of ethylene, as the proto- 
type of diatomic bromides. I have shown that the final product of 
this reaction is a diatomic salt corresponding to two molecules of 
chloride of ammonium. 
The further prosecution of the study of triethylphosphine in this 
direction has led me to investigate the derivatives generated by the 
* Phil. Trans. 1859, p. 177; and Phil. Mag. S. 4. vol. xviii. p. 71. 
