March 23, 191 1] 



NATURE 



121 



was still in hand when Mr. Goodfellow left. The snow- 

 capped mountain range rose steeply from the country at 

 its foot, and is inaccessible at most points. The heavy 

 rainfall in this range causes the rivers to rise rapidly in 

 flood, by which parties of the expedition were held up for 

 days unable to move. In spite of such obstacles, and the 

 flooded condition of much of the forest region, much 

 careful mapping, both of the Mimika and other rivers, 

 and of a part of the mountain range, has been effected. 

 Collections of birds, mammals, and ethnological objects 

 have arrived in England for study, but a large part of the 

 material obtained has yet to be received, including the 

 reptilian and entomological specimens. 



Thk Board of Agriculture and Fisheries has just pub- 

 lished a memoir of the Geological Survey on the water 

 supply of Sussex (supplement). The memoir contains 

 much new information which has accumulated since 1899, 

 when the original memoir was published. The subject is 

 dealt with under the headings of rainfall, springs, and 

 risks of contamination. Details are given of a large 

 number of wells and borings, together with analyses of 

 [Waters. A general index, covering the original memoir as 

 'well as this supplement, is included. Copies may be 

 obtained, price 25. 6d., from any agents for the sale of 

 Ordnance Survey maps, through any bookseller, or from 

 Mr. T. Fisher Unwin, i Adelphi Terrace, London, W.C., 

 who is the wholesale agent for the sale of Geological 

 Survey memoirs in the United Kingdom (except in the 

 County of London). 



The " Instructions to the Marine Meteorological 

 Observers of the U.S. Weather Bureau " (third edition), 

 a copy of which has reached us, are very complete, and 

 contain much useful information for general readers 

 interested in meteorology. Some photographs of types of 

 fog in the vicinity of San Francisco are very noteworthy. 

 Instead of several sets of observations required daily by 

 the former log-book, only one observation daily (except in 

 the case of storms) is now asked for, to be taken at 

 Greenwich mean noon. This large reduction in the 

 number of observations required has resulted, as was 

 hoped, in a great increase in the number of observers, 

 which now amounts to about 3000. These daily simul- 

 taneous observations taken over the entire sea are first 

 plotted on charts for the study of weather changes as they 

 actually occur ; afterwards they are tabulated, according 

 to months, in 5° squares of latitude and longitude, and 

 published in the monthly meteorological charts issued by 

 the Bureau and in the Pilot Charts issued by the Navy 

 Department. 



Mr. G. W. Pierce, author of " Principles of Wireless 

 Telegraphy," goes into the question of the best arrange- 

 ment of the circuits at a wireless receiving station in a 

 paper which appeared in the January number of the Pro- 

 ceedings of the American Academy of Arts and Sciences. 

 The distributed capacity of the antennae is treated as 

 localised to simplify the calculations, and the results 

 obtained will be sharper and more definite than can be 

 expected in actual practice. The author finds that best 

 resonance may be obtained with two values of the wave- 

 •length of the receiving circuits either above or below that 

 of the incident waves. He points out the advantage of a 

 low-resistance detector circuit on account of the superior 

 sharpness of the resonance effect obtained, and considers 

 that what is now required is a low-resistance detector 

 with a high efficiency which shall convert rapid into slow 

 alternate or into direct currents. 



The Electrician for March 3 contains an abstract of a 

 paper, presented to the Franklin Institute at Philadelphia 



NO. 2160, VOL. 861 



by Mr. Carl Hering, in which it is claimed that a con- 

 ductor carrying an electric current is subjected to a stretch- 

 ing force. In support of this statement, the author 

 describes some of the well-known experiments, or modifica- 

 tions of them, in which a circuit carrying an electric 

 current increases its area if any portion of the circuit is 

 movable. The trough experiment of Ampere, in which a 

 floating conducting bridge connecting two parallel troughs 

 of mercury moves away from the ends of the troughs at 

 which the current enters and leaves, respectively, may be 

 cited as an example. The " pinch " effect, that is, the 

 tendency of a liquid conductor carrying a current to con- 

 tract in section, which was discovered by Mr. Hering, is 

 given as a further proof of the stretching to which the 

 conductor is subjected. In our opinion, the view taken 

 by The Electrician in its leading article on the subject is 

 the more natural one, namely, that the whole of the 

 movements are explained by the repulsion by each other 

 of the magnetic lines of force of the various parts of the 

 circuits. 



In connection with the resistance-thermometer method 

 of demonstrating the existence of the Peltier and Kelvin 

 thermoelectric effects described by Mr. Starling in our 

 issue of February 16, Prof. W. Konig, of Giessen, has 

 directed our attention to two recent papers of his in the 

 Physikalische Zeitschrift and in the Archives of the Swiss 

 Soci^t6 de Physique, in which he describes a very simple 

 optical means of demonstrating the existence of the Kelvin 

 effect. The material is a U-shaped wire, the bend of 

 which dips into a mercury bath. The electric current 

 passes down one and up the other side of the U, and its 

 magnitude is so adjusted that the wire becomes red hot 

 for a short portion of its length. The two red patches are 

 found to be displaced upwards or downwards with respect 

 to each other, according to the sign of the Kelvin effect in 

 the material of the wire. Owing to the complicated nature 

 of the heat losses from such a wire. Prof. Konig has not 

 been able to make the method quantitative. 



We have received from Messrs. E. Leitz, of Wetzlar, 

 and Oxford Street, London, copies of their catalogues of 

 projection and photomicrographic apparatus. It is an 

 indication of the importance at the present time of such 

 appliances in scientific and educational work that these 

 complete catalogues are compiled and issued separately. 

 Until comparatively recent times such descriptions would 

 have been included in a general catalogue ; in fact, even 

 now it seems to be reserved to foreign manufacturers to 

 treat such matters with that thoroughness of which this 

 is a typical example. The apparatus described is, in many 

 cases, designed and constructed on established lines, but 

 in others, particularly in the application of photography 

 to micro-metallurgical work, the arrangements are both 

 novel and ingenious. The ordinary worker is particularly 

 indebted to Messrs. Leitz for introducing a small type of 

 arc lamp, which is of great efficiency considering its 

 small current consumption, may be used on any house 

 supply without special wiring or fitting, and yet gives 

 sufficient light for even the highest power photomicro- 

 graphic work. Both optically and mechanically^ the pro- 

 ducts of the firm now take a high place, and an inspection 

 of the apparatus referred to is sufficient to demonstrate 

 that it is well thought out by those who have practical 

 experience of the requirements of the worker in each 

 particular branch. 



Solid ammonium nitrite was isolated a year ago by 

 RAy, who showed that small quantities of the salt sub- 

 lime with decomposition when a dilute solution (07 to 2-0 

 p<r cent.), prepared by the interaction of silver nitrite 



