18 



HATCH EXPERIMENT STATION. 



[Jan. 



In Table II. is shown a similar series of experiments, with 

 modilications in the strengths of currents and methods of 

 treatment. The currents, however, are reduced in all in- 

 stances with favorable results. Nos. 6 and 7 received dif- 

 ferent treatment from those shown in the preceding table. 

 In No. 6, termed atmospheric electricity, the current was 

 obtained from a pole 35 feet above the ground ; from the top 

 of this pole there projected 24 small copper points, distrib- 

 uted in two circles, the outer arc having a radius of 30 

 inches. The arrangement was similar to that shown in Fig. 

 2, but not identical. The copper points were all connected 

 with a single wire leading to the copper plate electrode of 

 Box No. 3, the other electrode being grounded, as shown 

 at G. The electrical potential was not determined in this 

 experiment, but the deflection of the needle of a sensitive 

 galvanometer showed that a current was present in the 

 soil. 



In No. 7, copper and zinc plate electrodes were simply 

 connected together with a wire ; this formed a cell in itself, 

 and generated a current, usually about the optimum, which 

 could be readily read with the milannneter. The results of 

 the experiments are shown in the last column at the bottom 

 of the table. 



Table III. — Slionnng the Effect of (Utrrcnt FAectricUy ujwn the Growth 

 of Radishes (^Rtvphanns sdtirns L.). Normal Plants taken as the 

 Standard at li)0. 



[Duration of experiment, ,% days.] 



No. 



9 

 10 



Treatment. 



Normal 



Direct current; one .uravity cell; cop- 

 per plate electrotles, . . . . 



Amospheric electricity; copi)er jilate 

 electrodes 



Total 

 AVeight, in 

 Gkams, of — 



Roots. 



700 



soo 



900 



Tops. 



2,700 

 2,900 

 3,000 



Per Cent. 



gained in 



Weight of- 



Roots. 



14.28 

 28.59 



Tops. 



7.40 

 11.11 



Total 



Per Cent. 



gained. 



8.82 

 14.70 



Per Cent. 

 Total weiglit, in grams : — Normal. Treated, gained. 



Of roots 700 , 850 21.42 



Of tops 2,700 2,950 9.25 



Of wliole i.lant, . ..>-... ;!,400 3,800 11.76 



