62 MASSACHUSETTS HORTFCULTURAL SOCIETY. 



light bouse to twenty-six in tlie dark house. And it should also 

 be said that the average size of the tubers graded as marketable 

 was less in the light house than in the other. A portion of a 

 plantation of radishes in the light house was protected by the fan- 

 shaped shadow cast by an iron post an inch and a half in 

 diameter. In the shadow the foliage was scarcely injured, while 

 those leaves which projected into the light were curled. Chemical 

 analysis showed that the plants under the electric light had 

 reached a greater degree of maturity than those in the normal or 

 dark house. The ash was more, potash more than double, 

 chlorophyll (including extracted gums) somewhat more. The 

 total nitrogen was essentially the same in all samples, but it was 

 noticeable that in the electric light plants more of the amide 

 nitrogen had been changed into other forms than in the other 

 sample ; and the electric light samples were richer in albuminoids. 

 The light house plants from the shadow were much nearer in 

 composition to those in full light than to those in the dark house. 



Dwarf peas in the light house, particularly those in direct light, 

 blossomed about a week in advance of those in the dark house, 

 and they gave earlier fruits, but the productiveness was less, 

 being in the ratio of four in the light house to seven in the 

 dark house ; and the plants were considerably shorter in growth. 

 The decrease in production was due largely to the fewer peas 

 in each pod, for the number of fruitful pods produced in each 

 case was as seven in the light house to nine in the dark 

 house, and there were many seedless pods in the light house. In 

 other woi'ds, the production of pods (or flowers) was about the 

 same in both houses, but the plants in the light house produced 

 onl}' four-sevenths as many seeds as those in the dark compart- 

 ment. 



Carrots gave wholly indifferent results. They did not appear to 

 be affected greatly even by the naked light, though growing but 

 three or four feet away. Carrots require a long period of growth 

 and were therefore exposed to the light for about four months, 

 and yet the plants which grew directly in front of the lamp were 

 but little inferior to those which stood ten or twelve feet away, or 

 even to those in the dark house. No other pljtnt in our experi- 

 ments has withstood the electric light so well. 



Here, then, was proof that two distinct series or classes of 

 results proceeded from the naked electric light : plants are injured, 



