292 THE GARDENER. [July 



electric light ; but so many changes by way of ex]»eriment have been 

 made during the period alluded to, that it would notl)e just to consider 

 that either in house No. I or in house No. 2 has it yet had a fair 

 trial. 



My object is not to criticise the work, but rather to draw attention 

 to some of the results originally expected, and to consider how far they 

 are likely to be realised. 



It was suggested by its promoters that the ])rovision of the alternate 

 influence of light and darkness during the twenty-four hours was not 

 necessary for plant-life. That, by the aid of electric light, the colour- 

 ing matter of chlorophyll in the leaves of the plant could be produced ; 

 that it aids the growth of plants ; that it will counteract the effects 

 of night frosts, and will promote the setting and ripening of fruit in 

 the open air. That plants when growing continuously, as in the arctic 

 (northern was intended) summer, develop more brilliant flowers, and 

 larger and more aromatic fruits, than when grown under the usual 

 old-fashioned way of light, followed by its diurnal absence or darkness. 

 Now let us try and consider how the matter really stands. 



1. Light and heat (whatever their physical differences may be) al- 

 ways travel together in lines or rays, as they are called, from the sun 

 to the earth. Their joint use in plant-life is supposed to be fairly 

 understood and appreciated ; but it is not so easy to say accurately' 

 whether one of them, separated from its companion, is a more active 

 promoter of any function of plant-life than the other. But when light 

 and heat are made to travel by different routes, and arrive at the plant- 

 house by different vehicles (excuse the word), as light by the electric 

 lamp, and heat by the hot-water apparatus, it is hardly safe to conclude 

 that they viH do the work as well as when harnessed together as in a 

 sunbeam. 



2. Supposing the plants of the northern (not arctic) summer to 

 be similar to those that horticulturists here would wish to grow, it 

 does not follow, even if continuous light — that is, solar light, followed 

 on by electric light — had been applied during our summer months 

 when the temperatures of the external atmosphere of air and of soil 

 would have been more congenial to plant-life, that the same results of 

 a northern summer would have been obtained here, even if these 

 results are desirable. They were stated by Dr Schiibeler in effect to be 

 — that the further north we go within certain fixed limits, the more 

 energetic is the development of the pigment in flowers, leaves, and 

 seeds ; while the aroma of wild and cultivated fruits is much greater 

 than that of the same fruits in more southern countries, but that this 

 excess of aroma coexists with an inferior degree of sweetness. Such of 

 us as are gardeners will at once see that one of the important factors 

 in the question is the wood being well ripened during the northern 

 summer; another, the inspissated state of the sap of the plant, probably 

 arising from the dry state of the atmosj^here ; and a third is long rest 



