32 



NATURE 



\_May 9, 1872 



flows down over the copper plate at the bottom, and in 

 less than five minutes the cell is in full work. 



We have at present forty cells such as 1 have just de- 

 scribed. The average resistance of one cell is o'lg of an 

 Ohm. The electro-motive force of a Daniell's cell is i 07 

 Volts. 



The second form of cell is of the following construction. 

 A shallow wooden tray, square, and with slightly slanting 

 sides, is lined with sheet lead ; and this, after being elec- 

 trotyped with copper, forms both the containing vessel 

 for the liquids and the copper plate of the cell. Copper 

 trays were used at first, but they were soon eaten through 

 by the solution. The lead is not attacked at all. The 

 length of a side of the lead tray is 2iin., and its depth is 

 3jm. In each corner is set a small block of wood 

 i.^in. high. The zinc plate, which is like a square grid- 

 iron, rests at its corners on these blocks. The zinc has 

 parchment paper tied round its lower surface and sides. 

 The cell is filled up with saturated solution of sulphate of 

 zinc, and crystals of sulphate of copper arc dropped in 

 when required round the edges outside the parchment 

 paper. For connecting these cells together in series, the 

 lead lining is carried over the wooden tray at the corners 

 and down the outside to the under surface of the bottom 

 of it. Here it is soldered to a small squai'e of thick sheet 

 tin. The cells are piled up one on the top of the other, 

 the tin plates of the second cell resting on the zinc of the 

 first, and so on. The tin connections— a suggestion of 

 Mr. Varley — are most excellent. Two of these cells are 

 shown in section Fig. 5. The resistance of each of these 

 cells is on an average 019 of an Ohm. They are now 

 used at all the telegraph stations where Sir William 

 Thomson's siphon recorder is employed. 



In using these batteries in a laboratory where they are 

 not perpetually at work, the best way of managing them 

 may possibly be not to charge them with sulphate of copper 

 except when they are about to be used, and only to put in 

 as mucn as will do the work required. To calculate the 

 qu mtity is easy ; and any small excess might be worked 

 off through a low resistance. We have been keeping them 

 at work almost night and day. They require no attention 

 except to be occasionally supplied with sulphate of copper 

 crystals, and to have the sulphate of zinc that creeps up 

 over their edges wipt-d away with a cloth. 



At present our battery is tested very frequently, gene- 

 rally once m fuur or five days. The electromotive force 

 and the mternal resistance of each cell is determmed. 

 We have now had the greater number of the eighty cells 

 in action lor threr months, and some of them for five or 

 SIX months. During all that time they have been most 

 saiisactory, the electromotive force of them having re- 

 mamed perfectly constant. 



We test them by means of the reflecting electrometer, 

 or the tangent galvanometer. 



J. T. BOTTOMLEY 



{To be continued.) 



NOTES 



After we went to press last week, a most cheering telegr.1111 

 was received in this country respecting the fate of Dr. Livingstone, 

 as follows: — ' Aden, May i, 1872. — The Abydos has re- 

 turned from Zanzibar. .She brings news that Dr. Livingstone 

 is safe with Stanley. The news is brought by natives." It 

 may (airly be hoped that still more authentic intelligence will 

 shortly be received respecting the fate of the great traveller, with 

 respect to whom such anxiety has been manifested in this 

 country. Another despatch speaks also of the destruction of a 

 large portion of the town of Zanzibar by a terrible hurricane on 

 April 15. 



The eruption of Vesuvius, respecting which we gave such 



details as were accessible last week, appears to be over. Whether 

 any scientific results have been obtained by any observers besides 

 I'almieri it is too early yet to know. We hope it may be so, 

 and shall return to the subject as soon as the authentic accounts 

 have been collated. 



The Annual Visitation of the Board of Visitors to Greenwich 

 Observatory will take place on Saturday, June isl. 



The President, Vice-President, and Council of the Pharma- 

 ceutical Society of Great Britain will hold a (onvcrsaiioiic at the 

 South Kensington Museum on Wednesday evening next, May 15. 



At a meeting of Convocation at Oxford last week, it was 

 cai-ried that in all the schools, except that of theology, examiners 

 might be appointed who were not members of the University. 

 The liberal change which had already been granted for the 

 Natural Science School will do much to widen the general 

 course of re.idiug at that University, and to prevent the studies 

 pursued there partaking too much of any narrow or special 

 character. 



Mr. Charles Tomlinson, F.R.S., lectures this evening at 

 the London Institution, Finsbury Circus, on Solution and Super- 

 saturation. 



At the Annual Meeting of the Literary and Philosophical 

 Society of Manchester, held on the 30th ult., the following 

 officers were elected for the ensuing year : — President, Mr. E. 

 W. Binney, F.R.S., F.G.S. ; Vice-Presidents, Dr. Jas. P. 

 Joule, F.R.S., Dr. E. Schunck, Dr. Robert Angus Smith, 

 F.R.S., and the Rev. W. Giskell ; Secretaries, Prof. H. 

 E. Rojcoe, F.R. S., Mr. J. Baxendell. As members of the 

 Council, Mr. Peter Spence, Mr. W. L. Dickenson, Mr. H. 

 Wilde, Mr. R. D. Derbyshire, Prof. Osborne Reynolds, Mr. W. 

 Boyd Dawkins, F.R.S., Prof. Balfour Stewart, F.R.S. Few 

 local societies can boast such a distinguished list of names 

 as the above. 



Two Scholarships of the annual value ot 30/. and 20/. respec- 

 tively, tenable for two years, have been founded by the Governors 

 of the Middlesex Hospital, for the encouragement of the study 

 of medicine and surgery, in memory of the late Francis Broderip, 

 ajnunificent benefactor to the hospital. These scholarships will 

 be open to competition, at the end of each winter session, 

 amongst the general students of the hospital who shall have com- 

 pleted their third year of study at the Medical College. The 

 successful candidates will be required to attend and work at 

 the hospital for a fourth year, during which period they will be 

 eligible for the various resident appointments. 



Two Scholarships, of the annual value of 25/. and 20/. re- 

 spectively, will be offered for competition at Middlesex Hospital 

 at the commencement of the Winter Session 1S72-73. Each 

 scholarship is tenable for two years, provided the scholar conducts 

 himself satisfactorily. These scholarships are open to all gentle- 

 men who commence their medical studies in October 1S72. 

 Successful candidates will be required to become general students 

 of the College. The examination will take place on September 

 27 and following days, and the result will be declared on October 

 5. The following are the subjects for examination : — Latin, 

 Greek, French or German, Mathematics, Natural Philosophy, 

 Chemistry, Botany, Zoology. Candidates will be examined in 

 any three of the above subjects they may select ; but only one 

 Modern Linguage and two out of the last three subjects .are per- 

 mitteil. An equal number of marks wdl be given to each sub- 

 ject, and candidates will be expected to attain a certain standard 

 of proficiency in the subjects they select. Candidates must send 

 in their names in writing, addressed to the Dean, at the Middlesex 

 Hospital, statmg the subjects which they elect for their exami- 

 nation, on or before September 24. 



