ELECTRO-CHEMISTRY 



2852 



ELECTRO-CULTURE 



the two or more instruments in 

 order to determine the time of 

 flight and the velocity. By analo- 

 gous arrangements fitted in the 

 barrel of the gun itself the velocity 

 of the projectile from the instant 

 when it begins to move in the 

 barrel till it leaves the muzzle are 

 determined. See Artillery; Gunnery. 

 Electro-Chemistry. "The de- 

 termination of chemical reactions, 

 that is to say, the splitting up of 

 bodies into their elements or into 

 other compounds and the forma- 

 tion of new bodies, by the aid 

 of electricity. Like most other 

 branches of science, it has two sides, 

 the purely scientific or theoretical, 

 and the applied. That an intimate 

 relation existed between the two 

 branches of physics, chemistry and 

 electricity, was suspected by the 

 early electricians ; its existence 

 was demonstrated when the two 

 Dutch scientists, Deimann and 

 Paets van't Troostwyk, at Haar- 

 lem in 1789, first decomposed 

 water into its elements by the aid 

 of electric sparks between the ends 

 of two wires in a glass tube, though 



may after all only be a particular and causing the process to be com- 

 form of electricity. It has been pleted in a much shorter time, 

 shown that when copper deposits For purifying sewage, ageing wines, 



they did not succeed at the time in 

 collecting the separated gases, i.e. 

 oxygen and hydrogen. 



The discoveries of Volta and the 

 classical experiments of Sir Hum- 

 phry Davy placed the new science 

 on a firm basis, though it was not 

 till 1834 that the true laws of 

 electro-chemical action were ex- 

 plained by Faraday. Helmholtz, 

 in 1847, suggested that the heat of 

 chemical reaction in a voltaic or 

 galvanic cell could be entirely 

 transformed into electrical energy, 

 a proposition that was further de- 

 veloped by Thomson (Lord Kelvin) 

 in 1851 Since then further re- 

 searches by many eminent scien- 

 tists, particularly Van't Hoff, Arr- 

 henius and Sir J. J. Thomson, have 

 only confirmed the profoundly in- 

 timate nature of the relationship 

 between chemistry and electricity. 



The chemist has long had his s 

 conceptions of the molecule and 

 the atom and of the constitution 

 of matter ; but the electrician has 

 now suggested that what has 

 hitherto been described as matter 



itself out of a solution of copper 

 sulphate on a piece of iron wire 

 introduced into the solution, the 

 action is really electrical ; and the 

 question is suggested whether 

 what has hitherto been called 

 " chemical affinity " is not a form 

 of electrical action. By either of 

 these two forms of energy we are 

 able to develop heat and light ; and 

 each is able to accomplish ends 

 which, to our present knowledge, 

 the other is not able to achieve ; 

 and it is certain that if we ever ob- 

 tain any definite conception of the 

 constitution of matter and the 

 real nature of the atom, it will be 

 reached by the aid of electro- 

 chemistry. 



On the practical or industrial 

 side electro-chemistry has given us 

 the art of electro-plating and of 

 electro -deposition generally, em- 

 bracing the electrical refining and 

 smelting of metals ; many metals, 

 such as sodium, potassium, alu- 

 minium, magnesium, which could 

 not otherwise 

 ^**^,~~'' ke P r duced on an 

 industrial scale; 

 the electrolytic pro- 

 duction of caustic 

 EL soda and potash, 

 chlorine and 

 bleaching powder ; 

 y of cyanamide and 

 I other ammonia 

 compounds, nitric 

 ^S^ acid, and artificial 

 |^^||^ fertilisers such as 

 ^ " nitrolime." Nor 



and preparing ozone, electricity is 

 coming more and more into daily 

 commercial use. 



Electro- Culture. Study of 

 effects of electricity on plants. 

 Currents of certain low strengths 

 appear to be beneficial to plants ; 

 strong currents soon cause their 

 collapse ; while currents of inter- 

 mediate strengths apparently set 

 up no particular reaction. The idea 

 of utilising an electric current, 

 either through the ground or in 

 the atmosphere, to stimulate the 

 growth of plants or increase their 

 yield, was preceded by the idea 

 of stimulating the growth by elec- 

 trifying the seeds themselves 

 before planting. The Abbe Nollet, 

 the French philosopher, about 

 1760, Berthollet, and Specnew 

 experimented in this direction, ap- 

 parently demonstrating that elec- 

 trified seeds generally germinated 

 earlier and gave higher yields, and 

 that a larger proportion of the 

 seeds germinated. 



There are three directions hi 

 which electricity has been applied 

 to growing plants ; by the setting 

 up of electric currents in the soil, 

 by electrically exciting the atmo- 

 sphere, and by providing artificial 

 light. The question as to which is 

 the better of the two first systems 

 is not yet determined. Careful 

 experiments carried out under 

 the direction of the Agricultural 

 Department of the U.S.A. have 

 shown that currents set up by 

 zinc and copper plates placed in 

 the soil near the plants and con- 

 nected by wires have much in- 

 creased the yields of tomatoes, 

 peas, beets, turnips, carrots, par- 

 snips, and lettuce; but upon the 

 whole the American experiments 

 suggest that an electrification of 

 the atmosphere produces still 

 better results. Electric light, if 

 shielded properly so as to cut out 

 the ultra-violet rays, gives much 



is its scope con- 

 fined to the 

 production of 

 inorganic c o m- 

 pounds ; chloro- 

 form, chloral, 

 and iodoform are 

 now being manu- 

 factured by its 

 aid, as well as 

 certain dyes. It 

 is being utilised 

 to faciState the 

 processes of tan- 

 ning, a current of 

 electricity being 

 passed through 

 the tanning pits 



Electro-Culture. Scenes at Fro!. D. Berthelot's ex- 

 perimental station at Meudon, near Paris. 1. Plant for 

 supplying the electric current. 2. Inspecting progress. 

 3. French beans grown, left, by electro-culture : right, 

 under natural conditions 



