NOTES ON RECENT RESEARCH. 



239 



Scytonema, and several matted leathery lichens. Besides these there are 

 xerophytic forms : Selaginella lepidophylla (a " resurrection plant ") and 

 S. rupestris are abundant on granite. Lastly xerophytic Mosses and 

 Liverworts occur. 



Of the halophy tic vegetation the following are characteristic plants : — 

 Sporobolus airoides, Suceda suffruticosa, and S. depressa, Spirostachys 

 occidentalism Larrea mexicana, and Frankenia Jamesii. 



The author concludes by considering the changes in prevalent forma- 

 tions due to agencies of civilisation or other causes. — G. H. 



Effect of Electric Light. 



Electro-horticulture. By F. W. Rane (Bull. 37, West Virginia 

 Agr. Exp. Stn. vol. iv., No. 1, p. 3 ; 1894). — In 1892 a series of experi- 

 ments was inaugurated for testing the relations of incandescent electric 

 light to plants grown in the greenhouse. Previous experiments had all 

 been with the use of the arc lamp (Cornell Exp. Stn. Bull. Nos. 30, 42, 

 and 58). [For effect of gaslight see p. 264.] 



After enumerating several objections to the arc lamp, the author 

 observes that the essential difference concerned in the present paper is 

 that in the arc light chemical rays predominate, while in the incandescent 

 light these are only slightly present. 



Professor Bailey found with the arc that the nearer the plant grew to the 

 naked light, the greater was the acceleration. The plants " ran to seed " 

 before edible leaves were formed, which were smaller and curled. An 

 opal globe secured partially better results. Still better results were 

 obtained by placing the arc light with a globe outside the glasshouse. 



In the experiments with incandescent lights, begun in 1892, in each 

 instance the light was suspended from the peak of the house and hung 

 2^ feet above the bed. For seven weeks a 16-candle power was used ; 

 subsequently a rosette of seven such lights was substituted, i.e. equal to 

 112-candle power. In one house (A) the single light was used continually 

 every night ; in the other (B) the plants were treated normally with 

 regard to Lettuces. The average weights of two varieties were in (A) 2 

 and 1*8 oz. ; in (B) 1*8 and 1*5 respectively. 



The result of using the seven lights together (i.e. 112-candle power 

 instead of 16). The heights of three varieties were as follows : (A) 13, 

 10, 9 inches ; (B) 10, 6, 7 inches. All the electric light Lettuce was 

 thought to be much more tender than in the other house. The weight 

 of each of the varieties was all in favour of the electric-lighted plants, 

 viz. one-eighth, one-fourth, one-sixth better respectively. 



Spinach soon showed the effects as follows : After growing in the two 

 houses (A) and (B) as before, from February 28 to March 21, from seed, 

 in (A) 7i inches, 11 inches, and 9 inches, in three beds. In (B) 4 inches, 

 4 inches, in two beds. A photograph shows the relative heights taken on 

 April 15 as in the proportions of 1 ft. 3 in., 3 ft., 1 ft. 6 J in. in house (A). 



Cauliflowers occupying the same beds as the Spinach had the follow- 

 ing differences in size : (A) 11 inches, 19 inches, 15 inches ; (B) 10 inches, 

 10 inches. But the author observes, although its growth was taller in the 

 light, it did not produce as fine heads as that in the dark house and 

 shaded portions of the light house. 



