NATURE 



[November 8, 1894 



lead, in a very finely-divided state, and that a charged acoumu- 

 lator simply represents an ordinary voltaic cell in which lead is 

 the negative element. In order to test this point, the author 

 has examined the behaviour of several forms of primary battery 

 in which finely-divided lead is useJ as the negative metal. In 

 the case of a Daniell cell consisting of a copper plate in a 

 saturated solution of c >pper sulphate and a plate of spongy lead 

 in dilute sulphuric acid, the liquids being separated by an 

 ordinary porous pot, the mean of several experiments gave the 

 value 064 volt as the electromotive force. A calculation 

 of the electromotive force of this cell, based on the heats 

 of formation of the different substances, gives 03 volt, 

 so that it would appear as if lead in this very finely-divided 

 state evolved more heat when it entered into combination than 

 under ordinary conditions. If this supposition is true, it is 

 necessary to add o'34 to the figures calculated for ordinary sheet- 

 lead, to allow for this "allotropic" modification of the metal. 

 If we apply this correction 10 the observed electromotive force 

 (I '6 volts) of an element consisting of PbO. and pure lead, we 

 get the quantity I '94 volts, which represents the electromotive 

 force of the element PbO. and spongy lead. The above values 

 can be utilised to calculate the quantity of heat necessary to 

 convert ordinary lead into spongy lead, the value obtained 

 ''^'''S 7 '4 calories. With a Daniell cell, as described a'love, in 

 which the spongy lead had a surface of one square decimetre, 

 and weighed 440 grms., the mean electromotive force was 057 

 volts and the capacity 1375 ampere-hours, the internal resist- 

 ance being about 01 2 ohms. This form of cell is subject to 

 the same objection as the ordinary form of Daniell, namely, that 

 after a time the copper-sulphate solution diffuses through the 

 porous pot, and the copper is deposited on the negative metal. 



The filtration of water on a large as well as on a small scale 

 has acquired quite a different significance since the bacteriology 

 of water ha; sprung into existence ; and it is as a u.seful, because 

 impartial cjntribution to this subject, that we welcome Surgeon- 

 Major Johnston's short treatise on "the relative efficiency of 

 certain filters for removing microorganisms from water." The 

 iavesligatiuns here rec )rded were made as qualifying work for 

 the degree of I). Sc. at Edinburgh University, and the experi- 

 ments were carried out in the Public Health Laboratory of the 

 University. The fillers examined were those known as the 

 .\tkios patent water filter, Maignen's table '• Filtre Rapide," 

 the Nordmeyer-I3erkefeId filter, and the Pasteur-Chamberland 

 filter. The first two filter-; are described as useless for sterilising 

 water, both of them not only allowing " micro- organisms to pass 

 through the pores," but affording " a suitable nidus for the 

 growth and multiplication of micro-organisms, which are found 

 in much greater numbers in the filtered water than in the un- 

 filtered." The " lierkefeld " and "Chambcrland " fillers were 

 more elaborately examined. The "Chamberland " cylinder 

 selected was one intended for slow filtration, and in comparing 

 the results obtained with it and the " IJerkefild" cylin ler re- 

 spectively, it must be borne in mind that the rate of filiation 

 through the latter was 5 J times greater than through the former, 

 although after Iwenly-four hours' continuoui filtration, the rate 

 was only 1 1 limes greater. Major Johnston's opinion, based 

 on his examination of these particular cylinders, is that "the 

 Pasteur-Chambcilan<l filter is the best and only one on which 

 reliance can be placed for perminenlly sterilising water." An 

 important pjint, and one which has been overlooked by the 

 author, is the temperature of the room in which the filters were 

 kept whilit under examination, i'rcudenrcich found that a 

 higher or lower temperature had a marked effect on the effi- 

 ciency of the Chambctlnnd filter. It is to be regretted that in a 

 thesis of this kind, purporting to have a bibliography, the aulhor 

 should have entirely neglected to mention or refer to, in any 



NO. I3OD, VOL. 51] 



way, a large number of important investigations on these par- 

 ticular filters published during the last few years in various 

 foreign journals. 



Mr. G. J. Sy.mons has contributed to part ii. of the Report 

 of the Chicago Meteorological Congress, an interesting summary 

 of early English meteorological literature, embracing the years 

 '337~'699- He only deals with some fifty books and pamphlets 

 contained in his own library, bat his special knowledge of 

 meteorological bibliography enables him to give some useful 

 particulars about these old works. We can only briefly refer 

 to a fi;w of ihem here. In the Bodleian Library at Oxford 

 there is (as far as is known) the earliest continuous weather 

 record in the world, containing observations by the Rev. W. 

 Merle from January 1337 to January 1344. A few copies of a 

 translation of this work were printed in 1891. These observa- 

 tions show that the weather at that lime was very similar to 

 what it is now. In 1670, "The Shepheard's Legacy" was 

 printed. This work is excessively scarce, and is the earliest 

 edition of what has since been reprinted many times as "The 

 .Shepherd of Banbury's Rules for judging the weather." In 

 1671 appeared "A discourse concerning the Origine and Pro- 

 perties of Wind," &c. This treatise is noteworthy as being pro- 

 bably the first in which the theories of the winds are compared 

 with details of the trade winds, monsoons, &o. In 1696 a work 

 entitled "New Observations on the Natural History of the 

 World of Matter," &c., by the Rev. T. Robinson, was published. 

 It gives the earliest description yet known of the strong local 

 wind known in Cumberland as the helm wind. The sub/ect of 

 this wind has been brought before the Royal Meteorological 

 Society on several recent occasions, and that Society appointed 

 a committee to collect information upon it. 



THt; November number of the Journal of the Chemical 

 Society has been published. It is almost entirely taken up 

 with abstracts of papers published in other journals. 



Messrs. R. Friedi..\nder and Son have sent us their 

 XatutiC NovitaUs, Nos. 14-19, 1894, and No. xxx. of the 

 quarteily list of their new publications. The lists are invalu- 

 able to those who wish to keep in touch with recent scientific 

 literature. 



The Quarterly Journal {'Ha. 201) of the Geological Society 

 contains several papers on the geology of Africa. Dr. J. W. 

 Gregory describes the glacial geology of Mount Kenya ; 

 Captain II. G. Lyons, the stratigraphy and physiography of the 

 Libyan Desert ; and Mr. H. Draper, the principal physical and 

 geological features of South-eastern Africa, and the occurrence 

 of dolomite in South Africa. There are seven other papers in 

 \.\\cJourniil, and sixteen plates. 



We have received parts iv. to vii i. of the ihird volume of 

 the Transactions of the Leicester Literary and Philosophical 

 Soctcly, extending from July 1S93 to July 1S94. The Society 

 holds general meetings, at which lectures of a more or less 

 popular character are given, and sectional meetings for the 

 r.:ading and discussion of technical papers. Its object is to 

 cultivate literature, science and art, and, judging from the 

 reports, good work is being done in each of these directions. 



It is well known that Dr. A. Bernthsen's " Text-book of 

 Organic Chemistry " is an excellent elementary account of the 

 principles o( organic chemistry. Dr. George McGowan's trans- 

 lation of the work, published by Messrs. lllackie and Son, was 

 reviewed in these columns in December 1S89 (vol. xli. p. 172). 

 A second English edition, revised and extended by the author 

 and the translator, has now appeared. It is virlnally a trans- 

 lation of \\\i fourth German edition, published last year, and 

 therefore various chapters have been recast in order to include 

 new developments ol t.lcir subjects. 



