SCiENTinC SUMMAIIY. 
93 
MECHANICAL SCIENCE. 
Radiation from Steam Boilers . — Some interesting experiments have been 
made by Messrs, Fox, Head & Co, at Middlesborough-on-Tees, on the effect 
of a non-conducting coating of cement in reducing the radiation of heat from 
the surface of steam boilers. The boiler experimented on had a superficial 
exposed area of 280 square feet. In the first experiment with the boiler un- 
covered, 14-8 cubic feet of water were evaporated per hour ; in the second 
experiment, the boiler having been covered with non-conducting cement, 
the evaporation was at the rate of 20-4 cubic feet per hour. The coal used, 
and the circumstances under which the water was evaporated, were exactly 
the same in the two cases. 
Liquid Fuel on Shipboard . — Messrs. Dorsett and Blythe, of the Patent 
Fuel Company’s Works, have ^fitted on board the Retriever, a screw 
steamship of 600 tons burden, an apparatus for the generation of steam by 
the combustion of creosote and other liquid hydrocarbons. The creosote is 
first evaporated in two small vertical boilers, or generators, and the vapour 
is then conducted to the furnaces of the steam boilers, in which it is burnt. 
At starting, an ordinary fire is kindled in the generators, and when the 
pressure of the creosote vapour rises to about 20 lbs. per square inch, a 
portion of the vapour is conducted into the firebox of the generators, and 
supplies all the heat subsequently needed for the evaporation of the liquid 
fuel. The Retriever has been tried on the Thames with perfect success, the 
apparatus working without a hitch, and the combustion being apparently 
perfect. It remains to be seen whether any practical difficulties in the 
application of the system will be found on more extended trial, and whether 
the economical results are such as to j ustify its adoption. 
Apparatus for exhibiting the Laws of Wave Motion. — An extremely in- 
teresting paper on the laws of wave motion, and on an apparatus for illus- 
trating them, by Professor 0. S. Lyman, will be found in Fngmeering , 
Nov. 6. The apparatus exhibits to the eye not merely the motions of the 
surface contour of a wave, but also the motions that are at the same time 
taking place below the surface, in the whole mass of liquid affected. 
Solar Engine. — Captain Ericsson has been making experiments on the 
utilisation of solar heat in the production of mechanical force. According 
to a notice transmitted by him to Engineering (Nov. 27), his experiments, in 
which the radiant heat of sunbeams of from 650 to 5180 square inches in 
section was concentrated on a small surface, do not altogether confirm the 
results obtained by Pouillet and Herschel with the small instruments 
hitherto employed for measuring the quantity of radiant solar heat. Further 
experiments are to be prosecuted, and in the mean time he states that several 
experimental engines have actually been constructed, actuated by the sun’s 
radiant heat. In some of these engines, atmospheric air heated to 480° by 
concentrating the sun’s rays is used ; in others, steam generated in the same 
way. A regular and continuous rate of 300 revolutions per minute has been 
attained by some of these engines. 
Lntercommunication in Railway Trains . — It has now been made imperative 
on railway managers to provide means of communication between passengers 
