into mechanical force, with a marginal loss of not more than 20 per cent.; frictional resistance and the deterioration of the materials composing the instrument, caused by continuous working, being reduced to a minimum. The principles involved in the construction of these machines have been known to scientific men for some years; but their practical introduction is due to M. Gramme, whose efforts have been the immediate cause of the marvellous advance that has been made in the last few years in the utilizing of electricity. We have already in this city examples of one form of electric action—I refer, of course, to the transformation of electric into heat energy, so as to produce incandescent electric light. The principal arguments in favour of electric light are that it is colourless, and thus enables us not only to see pictures and flowers by it as perfectly as we can by sunlight, but also to carry on photography and many other industries as well at night as during the day. It is free from those products of combustion which not only heat the lighted apartments, but substitute carbonic acid and deleterious sulphur compounds for the oxygen upon which respiration depends; and supports growing plants instead of poisoning them. Interesting experiments have for some time been made as to the influence of the electric light on wheat, oats, and barley, and it has now been conclusively proved that, so far from its having any harmful effect, cereals placed under the influence of an electric lamp grow much more rapidly than those which are exposed only to the light of the sun; whereas any one who has tried to keep plants in a room constantly lighted with gas knows only too well how prone they are to wither and die.
As we have lately heard, this light has already been introduced into English mines, and there can be no doubt but that it will ere long supersede gas in all public places and large halls; but it does not seem probable that it will for some time compete with it successfully as a means of lighting smaller buildings. The great convenience of gas for heating as well as lighting is a strong argument in its favour, whilst for the degrees of temperature ordinarily required electricity is hardly available. For intense heat, however—I mean above 1,800° C.—it possesses advantages that far surpass any offered by combustion. It is hardly too much to hope that ere long there will be in this colony iron furnaces worked by the current generated by neighbouring rivers or tidal waves. Owing to the comparative smallness of our towns, the great advantage of this as a means of avoiding smoke-fogs may not seem at present a question of practical importance, but when we consider the probable increase of factories, and the rapid growth of our cities, and that from the imperfect combustion of coal there is a constant exhalation of carbonic oxide,
