266 



ELECTRICAL ENERGY, STORAGE OF. 



simply. In the accumulator of M. de Kabath, 

 increased surface is obtained by the use of a 

 great number of thin, corrugated plates. Mr. 

 C. F. Brush, the inventor of the well-known 

 arc lamp bearing his name, has also experi- 

 mented extensively with lead accumulators, 

 and has produced one which his company in 

 this country intend to use for supplying incan- 

 descent lamps. His improvements consist in 

 various modes of constructing the plates, so as 

 to render them durable, and increase their 

 storage capacity. A storage-cell, which is in 

 fact a reversible Daniell battery, was devised 

 by Messrs. Thomson and Houston, of this 

 country, in 1879. This cell consists of two 

 sheets of copper placed horizontally one above 

 the other in a solution of sulphate of zinc. 

 The current, in charging, is sent through the 

 battery from the top to the lower plate, 

 when the upper plate dissolves, forming sul- 

 phate of copper, which floats upon the sulphate 

 of zinc. Metallic zinc is deposited upon the 

 lower plate. This cell will yield a current as 

 long as there is a chemical difference between 

 the electrodes ; that is, until the zinc is all re- 

 converted into the sulphate. This has been 

 modified by M. d' Arson val, who makes use of 

 an electrode of lead, or of carbon covered with 

 lead shot, and one of zinc. When the cell is 

 charged, the zinc is deposited upon the zinc 

 plate and the lead peroxidized. 



A battery which has received very little at- 

 tention, but which seems to be superior to any 

 other yet produced, is one invented by Mr. 

 Henry Button, of Ballarat, Victoria. It was 

 described by him in a paper before the Royal 

 Society, London, in December, 1881. Mr. Sut- 

 ton experimented with both the Plante and 

 Faure batteries, and tried many different com- 

 binations. He finally found that positive elec- 

 trodes of amalgamated lead produced the best 

 results, and, in experimenting with a view to 

 determining the best negative electrode, came 

 to the conclusion that, "by having negative 

 electrodes whose oxides should be soluble in 

 the solution, and which could be redeposited 

 from the solution, or by having metallic solu- 

 tions from which metal could be deposited, the 

 resulting solution being such that should, on 

 the oxidation of the deposited metal, combine 

 with the oxide and again form the original so- 

 lution," he would obtain " a powerful and con- 

 stant source of stored energy." To this end he 

 tried cells in which the negative electrode con- 

 sisted of zinc, iron, or copper, and the positive 

 of amalgamated lead, the liquid being in each 

 case the sulphate of the metal of the negative 

 electrode. Zinc was abandoned, because of the 

 necessity of amalgamating it to prevent local 

 currents, and the iron because of its oxidation 

 when the cell was not in use. The form of 

 cell, therefore, finally adopted consisted of an 

 amalgamated lead plate for the positive and a 

 copper plate for the negative electrode, the 

 liquid being sulphate of copper. The chemi- 

 cal action in this cell, when a current is sent 



through it, consists in the combination of the 

 oxygen of the decomposed solution with the 

 lead, forming a coating of the insoluble perox- 

 ide, and the replacement of the copper in the 

 solution by the disengaged hydrogen, the cop- 

 per being deposited on the negative plate. 

 "When the action is complete, the positive elec- 

 trode is oxidized, the negative coated with 

 copper, and the solution converted into hydric 

 sulphate and water. In discharging, the cop- 

 per is dissolved in the solution and the lead 

 plate reduced, the cell returning to its original 

 chemical condition. A practical form of the 

 cell consists of a series of amalgamated plates, 

 fitted in grooves in a box, as in Cruikshank's 

 trough-battery, the spaces between the plates 

 being filled with a solution of sulphate of cop- 

 per. The positive sides of the plates then be- 

 come peroxidized, and the negative sides coated 

 with copper. The inventor states that the cell 

 is in every way superior to the Faure, and, 

 wishing to preserve it free from any private 

 claims, he has refrained from taking out any 

 patents upon it. 



The value of the secondary battery as an 

 element in industrial applications of electricity 

 depends both upon its efficiency that is, the 

 percentage of the work expended upon it 

 which can be utilized and upon the cost of 

 production. This latter, of course, depends 

 directly upon the former, and both together 

 determine the investment necessary in any 

 case. It is chiefly as a question of investment 

 that the efficiency has importance, as the item 

 of fuel is a comparatively small one in com- 

 parison with that of the investment in any 

 considerable electrical plant. 



The Faure is as yet the only cell which has 

 been experimented upon to any extent, but the 

 results so far obtained by different experiment- 

 ers are discordant, and it is not yet known 

 what the efficiency of this cell is. There are 

 certain conditions that must be observed, both 

 in charging and discharging, and if these -are 

 not fulfilled the results may fall very far short 

 of the maximum. If the charging is done too 

 rapidly, part of the energy is wasted as heat 

 in the cell, and if the discharge takes place too 

 quickly, energy is also wasted by the produc- 

 tion of heat. Care must also be taken that 

 the cell is completely discharged. A peculiar- 

 ity of the secondary battery is that, after being 

 rapidly discharged, it will yield, upon standing 

 some time, one or more residual charges, which 

 may be greater than that first given off. In 

 order to charge such a battery with the least 

 loss of energy, the charging current should be 

 of ample quantity, and of an electro-motive 

 force but slightly in excess of that which the 

 battery can attain. The discharge should be 

 made through a resistance that will prevent 

 its being too rapid. The best rate of discharge 

 must be found by experiment. The first care- 

 ful experiments upon the Faure cell were made 

 at the Conservatoire des Arts-et-Mdtiers, in Jan- 

 uary of this year, by M. Tresca and his associ- 



