A/A' WILLIAM SIEMENS, J-'.R.S. 231 



I next removed the electric light into a palm house constructed 

 -f framed glass (8'6 m. x 14'4 m. x 4'4i m.) In its centre, a 

 Itaiiana palm and a few other small palms are planted, whilst a 

 derable variety of flowering plants are placed around the 

 interior. The electric light was placed at the south corner of the 

 house, as high as practicable, that its rays might fall upon the 

 plants in the same direction and at the same angle as those of 

 the sun during the middle of the day. A metallic reflector was 

 placed behind the lamp, so as to utilise all the rays as far as 

 possible. Some young vines are planted along the eastern 

 side of the house. Three pots of nectarines just on the bud 

 were placed on the floor at different distances from the light, 

 and also some roses, geraniums, orchids, &c. The temperature 

 of the house was maintained at 65 F., and the electric lamp 

 was kept alight from 5 p.m. to 6 a.m. for one week, from 

 February isth to February 24th, excepting Sunday night. The 

 period of the trial was hardly sufficient to produce very striking 

 effects, but the plants remained healthy. The vine nearest the 

 light made most progress, and the same statement could be made 

 ding the nectarines and roses. Other plants, such as 

 geraniums, continued to exhibit a vigorous appearance, and the 

 electric light appeared to impart the vitality necessary to prevent 

 the plants being injured through excessive temperature. This 

 experiment is important in showing that the electric light, when 

 put into conservatories, improves the appearance and growth of 

 the plants the leaves become darker, the plants more vigorous, 

 and the colouring of the flowers brighter ; but a further period of 

 time is necessary to establish this observation absolutely. The 

 effects produced by electric light in conservatories are very 

 striking, owing to the clearer definition of form and colour due 

 thereto. 



I decided in the next place to try the effect of the electric light 

 upon plants in the open air and under glass at the same time. 

 The regulator was returned to its first position, two metres above 

 the ground, with a sunken melon house on the one side, and a 

 sunken house containing roses, lilies, strawberries and a variety of 

 other plants on the other. Upon the ground between these were 

 placed boxes sown with early vegetables, and protecting walls were 

 erected across the openings of the passage between the two houses, 



