478 BEPOET — 1881. 



the sense of elongating the stalks of plants, the continnons stimulus of 

 light appears favourable for healthy development at a greatly accelerated 

 pace, through all the stages of the annual life of the plant, from the 

 early leaf to the ripened fruit. The latter is superior in size, in aroma, 

 and in colour to that produced by alternating light, and the resulting 

 seeds are not at any rate devoid of re-germinating power. 



Further experiments are necessary, I am aware, before it would be safe 

 to generalize ; nor does this question of diurnal rest in any way bear upon 

 that of annual or winter rest, which probably most plants that are not so- 

 called annuals, do require. 



The beneficial influence of the electric light has been very manifest 

 upon a banana palm, which at two periods of its existence, viz., during 

 its early growth, and at the time of the fruit-development, was placed (in 

 February and March of 1880 and 1881) under the night action of one of 

 the electric lights, set behind glass at a distance not exceeding two yards 

 from the plant ; the result was a bunch of fruit weighing seventy-five 

 pounds, each banana being of unusual size, and pronounced by competent 

 judges unsurpassed in flavour. Melons, also remarkable for size and 

 aromatic flavour, have been produced under the influence of continuous 

 light in the early spring of 1880 and 1881, and I am confident that still 

 better results may be realised when the best conditions of temperature and 

 of proximity to the electric light have been thoroughly investigated. 



j\Iy object hitherto has rather been to ascertain the general conditions 

 necessary to promote growth by the aid of the electric light, than the pro- 

 duction of quantitative results ; but I am disposed to think that the time is 

 not far distant when the electric light will be found a valuable adjunct to 

 the means at the disposal of the hoi'ticulturist, in making him really in- 

 dependent of climate and season, and furnishing him with a power of 

 producing new varieties. 



Before electro-horticulture can be entertained as a practical process it 

 would be necessary, however, to prove its cost, and my experiments of last 

 winter have been in part dii-ected towards that object. Where water- 

 power is available, the electric light can be produced at an extremely 

 moderate cost, comprising : carbon electrodes, wear and tear of, and 

 interest upon apparatus and machinery emploj^ed, which experience else- 

 where has already shown to amount to 6cl. per hour for a light of 5,000 

 candles. The personal attention requisite in that case consists simply in 

 replacing the carbon electrodes evei'y six or eight hours, which can be 

 done without appreciable expense by the under-gardener in charge of the 

 fires of the green-houses. 



In my case no natural source of power was available, and a steam- 

 engine had to be resorted to. The engine of six nominal horse-power 

 winch I employ to work the two electric lights of 5,000 candle-power each, 

 consumes fifty-six pounds of coal per hour, the engine being of the ordinaiy 

 high-pressure type, — which, taken at 20s. a ton, would amount to 6d., or 

 to 3d. per light of 5,000 candles. But against this expenditure has to be 

 placed the saving of fuel effected in suppressing the stoves for heating the 

 greenhouses, the amount of which I have not been able to ascertain ac- 

 curately, but it may safely be taken at two-thirds of the cost of coal for the 

 engine, thus I'educing the cost of the fuel per light to Id. per hour ; the 

 total cost per light of 5,000 candles will thus amount to 6d. + ld.^7d. per 

 hour. 



This calculation would hold good if the electric light and engine- 



