Page:Transactions NZ Institute Volume 16.djvu/38

xxxii. a poisonous compound which when in large quantities causes sickness and death, we can realize how vastly important the absence of smoke may be to the health of future generations.

At the same time it must be admitted that gas has as yet not been fairly treated; it has been regarded almost entirely as a means of lighting, not sufficiently as a means of heating, and hardly at all as a motive-power. Dr. Siemens (who has protested strongly against this mistake) confidently predicts that, before many years have elapsed, we shall find in our factories and on board our ships, engines, with a fuel consumption not exceeding 1 lb. of coal per effective horse-power per hour, in which the gas-producer takes the place of the present steam-boiler.

With regard to electricity as a motive-power, electric railways are already in existence in Ireland and in Germany; but scientific men seem of opinion that, except in cases in which natural sources of energy, such as hills and waterfalls, are found, it will be long before electric power can take the place of steam on ordinary railways. I need not point out, however, that this is a country in which such sources of energy abound everywhere. I trust that at no distant day the force which is now applied in the form of friction necessary to hold back the trains in their descent of the Rimutaka Hill, and which is now dissipated and lost in wear and tear, may be utilized for propelling the engines for miles of their journey along the level country.

Whilst speaking of scientific discoveries as applied to practical matters, I cannot leave unmentioned a process which, though extremely simple in itself, is likely to mark an era in the history of the colony, and greatly to increase its wealth. I refer to the freezing of meat, and other products which might perhaps be similarly treated. I may mention, in passing, that the object of the process is not, as might have been supposed, to change the temperature of the atmosphere, but to suspend the vivifying powers of the germs which are continually floating about in it. As Professor Tyndall has pointed out, in his lecture before the Royal Institution in 1877 and elsewhere, animal matter may remain uncorrupted for months exposed to the air, provided that air is rendered perfectly free from these germs; whereas the slightest contact with air in its ordinary impure state—a mere pin-hole in the vessel containing the clarified atmosphere, for instance—admits the germs, and corruption ensues. The attempt to exclude the atmosphere from meat during the passage to Europe has been made, and has been found impracticable; but the desired result has been obtained by chilling the air to such an extent that the vivifying power of these germs is suspended.