■^06 



NATURE 



[July 26, 1894 



I 



action on the alteration in the resistance of a " bad contact " 

 between an aluminium plate and an iron wire when electric 

 oscillations are set up in the circuit containing the coherer. It 

 was reported to Trof. Thomson that a certain electro-plater 

 at Philadelphia had found that he could not pursue his silver- 

 plating operations during a thunderstorm, and that if he left 

 his plating over-night, and a thunderstorm came on, the work 

 was invariably ruined. Prof. Thomson says : — " I was disposed 

 to be thoroughly sceptical, and expressed my disbelief in any 

 such effect. Being urged, however, I went to the silver- plater's 

 shop, which was a small one, and questioned the silver-plater 

 himself concerning the circumstances which had been reported. 

 While it was evident that he was not a man who h.id informed 

 himself electrically, I could not doubt that he had indeed stated 

 what was perfectly true, namely, that when his plating opera- 

 tions were going on and a thunderstorm arose,his batteries, which 

 were Smee cells, acted as though they were short-circuited, and 

 the deposit of metal was made at too rapid a rate. The 

 secret came out on an inspection of his connections. The con- 

 nections of his batteries to his baths were made through a num- 

 ber of bad contacts, which would not fail to be of high resistance 

 under ordinary conditions. I could readily see that virtually he 

 was working through a considerable resistance, and that he 

 had an excess of battery power for the work. Under these 

 circumstances a flash of lightning would cause coherence of his 

 badly-contacting surfaces, and would improve the conductivity 

 so as to cause an excessive flow of current, and give a too rapid 

 deposit. The incident suggests the employment of Dr. Lodge's 

 ingenious instrument in the study of the waves which are propa- 

 gated during thunderstorms, of which waves we have practically 

 little or no information." 



Prof. R. Lepsius, of Darmstadt, is preparing a new geo- 

 logical map of Germany, which will give a valuable summary 

 of our knowledge of that are.i. It is founded upon the various 

 national surveys and upon other good authorities. The scale is 



I : 500,000. The map will be complete in twenty-seven sheets, 

 each measuring 15^ inches by 13 inches. Kour sheets in the 

 south-western areas are published (by J. Perthes, Gotha) ; these 

 are: — Sheets 17, Koln ; 22, .Stnissburg ; 23, Stuttgart; 25, 

 Mtilhauscn. The sheets are completed beyond the German 

 Ixjunlary. The meridian of the map is Paris, but the longitude 

 east of Greenwich is also indicated on the upper margin of each 

 sheet. A new point in this map is that a complete index is 

 printed wiih each sheet, but only those rock-divisions indicated 

 on the sheet are coloured. The subdivisions shown may be 

 grouped as follows : — Post-Tertiary, 4 ; Tertiary, 4 ; Secondary, 



II ; Palaiozoic, 10; Metamorphic, 2; Volcanic and Plutonic, 

 7. The " Silur System " includes Cambri.in, Lower Silurian, 

 and Upper Silurian The map is unusually bright and clear ; 

 this is partly due to the black printing (topography, &c. ) having 

 been done last, over the colours. Like many other geological 

 maps recently published, the price is small : two marks for one 

 sheet, or three marks for each Licferung containing two 

 sheets. 



The generous manner in which reports on scientific matters 

 are prepared and published in the United States h-is frequently 

 been commented upon in these olumns. In 1891 the sum of 

 two thousand dollars was voted by Congress for investigations 

 respecting the advisability of establishing a fish-hatching station 

 in the Rocky M >untain region in the States of Montana and 

 Wyoming, and also a station in the Gulf States. The results of 

 ihete investigations are contained in a ^»//ir/in (vol. xi. 1891) 

 recently received from the U.S. Kiih Commission. Prof. B. W. 

 Evcrmann carried out the chief of the investigations. In look- 

 ing for a suitable site for a fish-cultural station, the following 

 requirements for the successful operation of such a station 

 NO. I 29 1, VOL. 50] 



were kept in mind : — (i) There should be a constant supply of 

 not less than one thousand gallons a minute, at a temperature 

 never exceeding 50° or 55°, and free from any possibility of 

 contamination. (2) There should be twenty to thirty acres of 

 ground conveniently near the source of water supply. There 

 should also be sufficient fall between the source of w.ater supply 

 and the hatchery building to permit a gravity supply. (3) The 

 location should be central with reference to the region to be 

 stocked, and should also aflibrd good railroad facilities. Prof. 

 Evermann and his pirty visited fourteen of the most promising 

 localities, and the explorations were very satisfactory, both froji 

 the economic and scientific points of view. It w.as eventually 

 decided that the region mostnearly filling all the natural require- 

 ments was Horsethief Springs. These springs, situated in 

 Montana, near the north-west corner of the Yellowstone 

 National Park, are among the largest and most remarkable to 

 be found anywhere in the United States. 



We are glad to see, from the "Abstract of Proceedings of the 

 South London Entomological and Natural History Society " for 

 the years 1892 and 1S93, which has just reached us, that the 

 condition of the Society is still a very satisfactory one, although 

 the membership is slightly lower now than a year ago. The ' 

 Society now numbers 192 members. The volume contains, in 

 addition to reports of the various meetings held, the addresses 1 

 of the respective presidents for 1S92 and 1S93. 



THt; London Matriculation Directory for June has just been 

 issued by the University Correspondence College, and contains , 

 the papers stt for the MatricuLation Examination, June 1S94, 

 and solutions to the same. 



A SECOND edition has been issued of the catalogue of the 

 " Bibliothcque du Jardin Botanique de Buitenzorg," Java. 

 The edition has been prepared by Dr. Brutel de la Riviere, 

 and it is much more complete and better arranged than the 

 first. We are requested to state that naturalists desiring to 

 obtain a copy of the catalogue, should communicate with M. 

 Treub, the Director of the State Botanic Garden, and the 

 volume will be sent without delay. 



The July part of the American Naturalist contains, besides 

 general n oles, articles on "Animal Mechanics," by Dr. Manly 

 Miles; "The Meaning of Tree-Life," by H. L. Cl.irke; 

 " Lepid osirenids and Bdelloslomids," by Theodore Gill ; and 

 " The Origin of Pelagic Life," by Prof. W. K. Brooks. 



The Quarterly Statement of the Palestine Exploration Fund 

 for July contains many items of interest, among which we 

 notice a translation of a paper by M. Th. Barrois, "On the 

 Depth and Temperature of the Lake of Tiberias." 



Messrs. Macmillan and Co. have just published a new 

 edition, revised and enlarged, of " Arithmetic for Schools," by 

 Rev. J. B. Lock. 



The Seventeenth Annual Report of the Connecticut Agri- 

 cultural Experiment Station has just been issued at New Haven, 

 and tells of a vast amount of work done during 1893. 



An interesting mode of convening oxide of iron into small 

 but perfect crystals of ha-matite, exhibiting the characteristic 

 forms of the naturally occurring mineral, is described by Prof. 

 Arclowski, of Liittich, in the current number of the Adtschrift 

 fiir Atiorgaitische Chemie. The experiment simply consists in 

 passing partially or totally dissociiitcd ammonium chloride 

 vapour over the oxide heated to a particular temperature. The 

 oxide is placed in a combustion tube clo-ed at one end, and al 

 the closed end a quantity of ammonium chloride. The portion 

 of the tube containing the latter is placed in a combustion fur- 

 nace, and that containing the ferric oxide in an air bath, so con- 



