ELECTRIC WAVES. 



ELLIS, WILLIAM. 



285 



zinc battery has been devised by M. Kohlfurst, 

 for giving a constant current, for one whole 

 year, at a cost of 1 H>. of crystals of sulphate 

 of copper. A truncated hollow cone is thor- 

 oughly varnishpd inside, filled with crystals 

 of sulphate of copper and placed mouth down- 

 ward in a glass jar deeper than itself. This 

 cone has notches round the rim, and has a 

 small hole in the centre at the top. The pos- 

 itive pole is a thick cake of zinc suspended 

 over the face of the cone ; it is cast with a 

 hole in the centre through which passes a gut- 

 ta-percha covered wire, which is connected 

 with the upper cone. The glass cylinder is 

 filled with water, and it is evident that the 

 rate of solution of the sulphate of copper de- 

 pends upon the facility with which it is dis- 

 solved by the access of water through the 

 notches in the cone, and, as this takes place at 

 a uniform rate, the current given by the bat- 

 tery is uniform also. A dilute solution of sul- 

 phate of magnesia or common salt may be used 

 instead of plain water, if it is required to di- 

 minish the internal resistance of the battery. 



Mr. H. Highton describes, in the London 

 Chemical News, a cheap and simple battery, 

 said to be nearly 50 per cent, higher in poten- 

 tial than a Grove or Bunsen, and 150 per cent, 

 higher than a Daniell. 



For negative, carbon packed in granulated carbon, 

 peroxide of manganese, and precipitated sulphur ;. the 

 liquid should be dilute acid sulphuric is best. For 



for positives. The internal resistance is rather large ; 

 if common salt or chloride of potassium be used in- 

 stead of caustic alkali, the internal resistance is much 

 less, but the potential sinks to a little more than 10 

 per cent, higher than a Grove. With dilute sulphuric 

 acid on both sides, the resistance is still less, but the 

 potential is only a little higher than a Grove. 



M. Gaiffe suggests the following simple form 

 of an economical galvanic pile, somewhat re- 

 sembling Calland's, but of different elements. 

 It consists of a vessel into which are dipped 

 two rods one of lead, the other of zinc. The 

 leaden one descends to the bottom ; the zinc 

 is one-half shorter. The bottom of the vessel 

 is coated with red oxide of lead (minium) ; and 

 the exciting liquid is water containing 10 per 

 cent, of chlorhydrate of ammonia. The elec- 

 tromotive force of this pile is said to be about 

 one-third of that of a Bunsen's pair ; its in- 

 ternal resistance is slight, and varies little; 

 the chloride of zinc formed does not sensibly 

 alter the conductivity of the exciting liquid; 

 its constancy is great; finally, the expense is 

 almost nothing when the circuit is open. 



ELECTRIC WAVES, VELOCITY or. The 

 velocity of electric waves through the Atlantic 

 cables has been ascertained, by Prof. Gould, 

 to be from 7,000 to 8,000 miles per second. 

 Telegraph-wires, upon poles in the air, con- 

 duct the electric waves with a velocity more 

 than double this. It is a curious fact that the 

 rapidity of the transmission increases with the 



distance between the wire and the earth, or 

 with the height of the support. The Journal 

 des Telegraphes says that wires, placed on poles 

 slightly elevated, transmit signals with a ve- 

 locity of 12,000 miles a second ; and those at 

 a considerable height give a velocity of 16,000 

 or 20,000 miles. 



ELLIS, Rev. WILLIAM, an English mission- 

 ary, traveller, and author, born in London in 

 1795 ; died in London, June 25, 1872. In Jan- 

 uary, 1816, after obtaining a good education 

 at one of the dissenting colleges, he sailed 

 with his wife for the South-Sea Islands, as a 

 missionary of the London Missionary Society. 

 He was stationed at Tahiti, or Otaheite, and 

 set up there the first printing-press in the 

 South-Sea Islands. He returned to England 

 in 1824, on account of the illness of his wife, 

 and was employed for some years at home in 

 the business of the London Missionary Society, 

 and from 1833 to 1840 was the Foreign Secre- 

 tary of that society. His wife died in 1835, 

 and in 1837 he married Miss Sarah Stickney, 

 a distinguished teacher and author, residing at 

 that time in Hoddesdon, in Hertfordshire, who 

 had been educated among the Society of 

 Friends, to which both she and her parents 

 belonged. In 1853, while still retaining his 

 connection with the London Missionary So- 

 ciety, Mr. Ellis was sent by its Board of Man- 

 agers to Madagascar, to inquire into the con- 

 dition and prospects for a resumption of their 

 missions there, which had been suspended in 

 consequence of the violent opposition and per- 

 secution of the reigning queen. He made 

 three visits to the island within the next 

 three years, and published a narrative, of 

 great religious and scientific interest, of the 

 results of his explorations when, in conse- 

 quence of the death of the pagan queen, and 

 the favorable disposition of her son and suc- 

 cessor to Christianity, the missions were rees- 

 tablished, and met with the most remarkable 

 success. Mr. Ellis again (in 1865 or 1866) re- 

 visited the island, and spent some time in en- 

 couraging the missionaries and native Chris- 

 tians. Mr. Ellis published many works, nearly 

 all having primary reference to missionary 

 work, but containing a vast fund of interesting 

 geographical and scientific information. The 

 most important of these were: "Missionary 

 Narrative of a Tour through Owhyhee," 1826 ; 

 "Polynesian Researches," 2 vols., 8vo, 1829; 

 "A Vindication of the South Sea Missions 

 from the Misrepresentations of Otto von 

 Kotzebue, with an Appendix," 1831; "His- 

 tory of Madagascar," 2 vols., 1838 ; " History 

 of the London Missionary Society," 8vo, 1844; 

 " Village-Lectures on Popery," 1851 ; " Three 

 Visits to Madagascar during 1853-1856, with 

 Notices of the People, Natural History, etc.," 

 1858; "Madagascar Revisited, describing the 

 Events of a New Reign, and the Revolution 

 which followed," etc., etc., 2 vols., 1867. He 

 nlso edited " Stewart's Visit to the South 

 Seas," and wrote an "Introductory Essay on 



