44 



NATURE 



\Nov. II, 1880 



the prism-shaped steel bed, on which the middle knife-edge rests 

 is easily drawn out with the finger from die swallow-tail shaped 

 rollers between which it is passed in the body of the balance. 

 The beam can thus be easily removed and replaced. The balance 

 rests on four feet. The stopping and raiding arrangement is con- 

 tained in a horizontal frame. Each weighing scale hangs on a 

 conical point. Passing on to the reading, we find that the accu- 

 racy with which the balance works is, with 20 kg. weight, 2mg., 

 with 500, 3i mg. ; and this is gained by substituting for the 

 pointer an optical arrangement on the beam, consisting of two 

 achromatic glass prisms, which render parallel the rays from 

 opposite directions and send them to a telescope placed before 

 the balance. At the two sides of the balance, about 2m. to 4m. 

 from the middle knife-edge, two scales are set (best on the walls 

 of the room) ; the images of these scales move in the field of the 

 telescope beside each other in opposite directions, and so the 

 corresponding divisions can be read off. These readings are 

 independent of vibrations of the telescope, and are much more 

 exact than those with telescope and cross threads, not to speak 

 of the common pointer. The arrangement also permits of the 

 centre of gravity of the balance being placed lower, the stability 

 increased, &c. The weight of the balance is scarcely 20 kg., 

 though both scales can carry 20 kg. weight. 



Experiments by Forbes in 1831 and by some others since 

 seemed to warrant the view, now commonly held, that the metals 

 fall into the same series as regards conduction of electricity and 

 conduction of heat, that the quotient of the heat conductivity by 

 electric conductivity is nearly constant, llerr H. F. Weber, 

 inclined to doubt this as contradicting the view (proved for gases 

 and liquids) that the amount of heat transferred within a substance 

 from layer to layer is most intimately connected with the specific 

 heat of unit volume, made new experiments in this relation 

 (which he has described to the Berlin Academy). He measured 

 the heat-conduction by observing tlie cooling of various metal 

 rings in a space at constant temperature, and the electric conduct- 

 ing power of the same rings, by noting their deadening effect on 

 the oscillations of a magnet. The result confirmed his anticipa- 

 tions, the quotient of heat-conduction by electric conduction 

 being found in the closest connection with the specific heat of 

 unit volume. Experiments by a different electrical method for 

 metals conducting electricity badly (lead, bismuth, c&c.) and for 

 mercury gave the same result. (Ten metals in all were examined.) 

 On the other hand, non-metallic conductors of electricity do not 

 show the relation in question ; e.g. the heat-conduction of carbon 

 is at least twenty to thirty times greater than that calculated 

 from the electric conductivity and the specific heat. Thus the 

 relation seems to be connected with the metallic nature of the 

 substance. Herr Weber found the heat-conducting power of all 

 the solid metals examined to decrease with increasing tempera- 

 ture, but at a considerably less rate tlian the electric conductivity. 

 He further offers explanations of the erroneous view adopted, 

 noting, inter alia, that the experiments in one case, though 

 exact, were on too few metals, and these had nearly the same 

 specific heat. 



Prof. R. B. Warder of Haverford College (Pennsylvania) 

 and Mr. W. P. Shipley have investigated the configurations 

 assumed by floating magnets in a magnetic fluid. They have 

 modified Prof. Mayer's original experiment by surrounding the 

 vessel of water with a coil of wire traversed by a current, thus 

 producing a field of force which, while still symmetrical about 

 the centre, differs in several respects, the lines of force not being 

 so greatly concentrated near the centre. Diagrams of various 

 configurations are given by these experimenters in the American 

 Journal of .Science for October. As even a single one-fluid cell 

 produces a current sufficient t'j show these results, they ought to 

 be easy of repetition. 



A COMPREHENSIVE memoir on the theory of the radiometer, 

 by M. Mees, appears in the Proceedings of the Amsterdam 

 Academy, and (in pretty full abstract) in Wieil. BeibL, No. 7. 

 The author, after criticising the various theories that have been 

 enumerated, which lie arranges in three classes, offers his own 

 explanation of the phenomena (which cannot be briefly stated 

 here). 



A FEW months ago we drew attention to certain results 

 published by Herr Exner of Vienna, relative to thermoelectricity, 

 and which were at variance willi all the body of evidence existing 

 in that branch of science. Herr Exner had in fact asserted that 

 an antimony-bismuth couple possesses thermoelectric powers only 

 £0 long as one of the two metals is in contact with oxygen or 



with a gas capable of acting on one of them. The w ish we then 

 expressed that .some independent observations might be made by 

 other physicists has met with a response across tlie Atlantic. 

 Prof. C. A. Young of Princeton, N.J., communicated to the 

 recent meeting of the American Association a paper on the 

 thermoelectric power of a platinum-iron couple in vacuo. The 

 crucial experiment was made witli an exhausted glass tube con- 

 taining an iron wire with platinnm terminals, the terminals being 

 again fastened to iron wires lea ling to a galvanometer. The 

 tube was exhausted to one-millionth of an atmosphere. On 

 laying the apparatus in the sunlight and alternately sliading the 

 internal or external junctions an electromotive force could be 

 produced, which was found to be equal in eveiy case. The 

 conclusion Prof. Young draws from the experiment is that Exner 

 is wrong in his statement that thermoelectric electromotive force 

 is due to the action of the gaseous media in which the metals are 

 plunged. The experiment was conducted in Mr. Edison's 

 laboratory at Menlo Park. 



GEOGRAPHICAL NOTES 

 The glacier of the Zarafshan, one of the greatest in Central 

 Asia, which has hitherto been very imperfectly known, was ex- 

 plored during this summer by MM. Mushketoff', geologist, and 

 Ivanoff. The exploration was quite successful, and at the last 

 meeting, October 26, of the Mineralogical Society at St. Peters- 

 burg, Prof. Mushketoff read a paper on his explorations. The 

 lower extremity of the glacier is at the height of 9000 feet. Tlie 

 Galtcha people, who inliabit the upper valley of the Zaraf.shan, 

 have never ascended the glacier ; they say that on the summit of 

 it there are two great pillars of stone, between which the traveller 

 must go, and tliat the pillars would certainly crush together if 

 any one ventured into the icy solitude. On August 25 the party 

 began the ascent of the glacier on a very steep slope covered 

 with blocks and moraines. A tunnel, no less than ,3500 feet 

 long, rans under the glacier, being the bed of the Macha River. 

 After two days' travel the party had done seven miles on the 

 glacier. The temperature during the day was as high 35^40° Cels. , 

 and during the night as low as — S° ; some Galtchas who accom- 

 panied the party fell ill with fever. On the fourth day the party 

 reached the first watershed, or rather the first iceshed; the 

 whole length of the glacier to this point was sixteen miles, the 

 width being one mile ; six other glaciers, each of -nhich is greater 

 than the greatest Alpine glaciers, fed the principal one. At the 

 head of it there is a wide citqiie opening to the east ; several 

 peaks around it reach 20,000 feet. The descent on the other 

 slope of the mountain ridge was far more steep and difficult than 

 the ascent ; the crevasses are very numerous and the glacier 

 has several great " ice-falls," the inclination of which is no less 

 than 50 degrees ; the party was compelled to make use of small 

 anchors and to cut steps in the ice. Two men were unwell and 

 quite unable to go further when the party reached the foot of 

 the eastern slope, after a very difficult journey. 



The last number of the Izvestya of the Rus'ian Geographical 

 Society contains a letter from Dr. Miklukho-Maclay. After 

 having visited the islands of New Caledonia, Lifu, New Hebrides, 

 Admiralty, Louisiade, &c., he reached, about the end of January, 

 18S0, the south-eastern coast of New Guinea; here he explored 

 several points of the coast, and thence went to the islands of the 

 Torres Strait and to Somerset, to study the population of 

 Northern Australia. On his voyage from Vaihan Island to 

 Sydney he stopped at several points of the eastern coast. From 

 Sydney M. Maclay proposes to go to Japan, and thence to return 

 to Russia. During his stay in Brisbane he was very kindly 

 received by the local government and by private persons, who 

 have much facilitated his anatomical studies by allowing him to 

 work in the old museum and to make use of the photography of 

 the topographical department. The journey in the interior of 

 Queensland was very much facilitated by the cordial reception 

 he received from the .■■quatters, and by the kind permission to 

 travel gratuitously along all the railways. M. Maclay expresses, 

 in a letter addresied to the Golos, his thanks to the Australians 

 for the reception he met from them, and wishes that all men of 

 science were so kindly received in Russia. On August 12 he 

 was in the house of J. B. Bell at Jimbor, near Dallby. The 

 Russian public subscription has already reached 606/. which he 

 received at Sydney. 



A GOOD example is being set by the Tashkent College. 

 During the summer fourteen pupils of the College, under the 



