1922.] 



Electro-Culture . 



79a 



The scientific aspect of the work will be more fully dealt with 

 iu two papers which Prof. V. H. Blackman is contributing to 

 the "Journal of Agricultural Science." The Committee has 

 now been at work for five years and has issued four interim 

 reports* : the work completed in 1922 which was undertaken 

 on lines suggested by the experience of previous years 

 p]-omises very striking results, but an account of that vrork 

 must await the fifth interim report of the Committee which 

 has not yet been presented. 



In view of the complexity of the subject the Committee have 

 confined their experiments to electro-culture by means of over- 

 head discharge. Field experiments have been carried out for 

 the Committee by Professor Y. H. Blackman at Rothamsted 

 with barley (1918 and 1920), winter sown wheat (1919 and 

 1920), winter oats (1921) and clover hay (1919, 1920 and 1921); 

 at Lincluden ^Dumfries) with oats (1918, 1919 and 1920), and 

 potatoes (1921); and at Harper Adams Agricultural College with 

 oats (1919, 1920 and 1921), clover hay (1920) and pea and oat 

 mixtures (1921). Pot-culture experiments have been carried out 

 by Professor Blackman at Rothamsted in 1918, 1919, 1920 and 

 1921, with wheat, maize and barley; laboratory experiments to 

 determine the eft'ect of electric currents on the growth of plant 

 organs have also been undertaken. 



Field Trials. — Apparatus. — The apparatus at Lincluden con- 

 sisted of a mercury interrupter, supplied with a direct current at 

 a voltage of 60, an induction coil and three Lodge valves in 

 series. At Rothamsted it consisted of a petrol-driven " Delco " 

 set, with at first a dry transformer and later an oil-cooled trans- 

 former, and a Newton .and Wright disc-rectifier. At the 

 Harper Adams Agricultural College current (100 volts D.C.) 

 v;as available from the small electric lighting installation of 

 the College. The apparatus consisted of a 2-h.p. motor coupled 

 to a one K.V.A. A.C. generator (140 volts) which bore on an 

 extension of its spindle a Newton and Wright disc-rectifier. 

 An oil -cooled transformer (l-K-V-A.^* giving a voltage up to 

 60,000 was employed for the discharge current. 



Field InfttaUation. — A steel cable supported on high tension 

 insulators was fixed at a height of about 7 ft. at each side of 

 the electrified areas and fine galvanised steel w^ires (gauge 29) 

 spanned the distance between the cables. The wires were 

 5 or 10 ft. apart. The aerial installation was made positive. 



* To be obtiiinod free 011 application to the Secretary to the Committee, 

 ¥Jr. W. l\. Black. B.Sc. Ministry of Agriculture. 10. Whitehall Place, S.W. 1. 



