58 



NA TURE 



[May i6, 1907 



is applicable to motor-cars, flyin,e;-machines, and other 

 structures. 



Dr. C. G. Seligniann gave a kincmatograph exhi- 

 bition of native dances taken during the course of the 

 Daniels ethnographical expedition to British New 

 Guinea. The demonstration by Dr. Hele Shaw was on 

 the subject of aerial gliding. During the last few years 

 a large number of experiments have been made in con- 

 nection with aeroplanes and machines for soaring and 

 gliding. Dr. Shaw gave a brief account of the work 

 of Lilienthal, the U'right Brothers, and others, and 

 summarised the present state of our knowledge on the 

 subject. 



Two exhibits of particular interest were apparatus 

 of pure iridium and rhodium and of fused silica by 

 Messrs. Johnson, Matthey and Co., Ltd. This firm 

 has succeeded in producing iridium and rhodium of 

 such e.xtreme puritv as to render these hitherto prac- 

 ticallv unworkable metals so malleable as to enable 

 their being used for the manufacture of such appar- 

 atus as basins, tubes, and flasks. These metals, having 

 a verv high melting point, and being almost unat- 



Transparent Silica Apparatus. 



tacked by acids, should prove of great value in chemical 

 research. The scientific work of which the process of 

 manufacturing apparatus of fused silica is the out- 

 come was carried out by two English men of science 

 about ten years ago; unfortunately, as so often hap- 

 pens in these cases, its commercial importance was 

 first recognised in Germany, and its production on an 

 industrial scale commenced, little or nothing of a 

 similar nature being attempted at home. Messrs. 

 Johnson, Matthev and Co. have now taken up the ori- 

 ginal process, and bv suitable modifications to meet 

 industrial requirements are enabled to place this 

 material upon the market at a price which can no 

 longer be considered prohibitive. The apparatus is 

 manufactured from the purest silica obtainable. .\t 

 a high temperature this substance melts, and yields a 

 viscid liquid which can by suitable means be fashioned 

 into apparatus having all the appearance of ordinary 

 glass, as is shown in the accompanying illustration. 

 The apparatus possesses many properties which are 

 likely to render it of great service both to science 



NO. 1959, VOL. 76] 



and to industry; e.g., it can be made white hot anc 

 plunged into water, or otherwise rapidly cooled, with- 

 out any danger of cracking ; it is quite unattacked by 

 water or acids, while ordinary glass under similar 

 conditions is appreciably dissolved. 



In the subjoined summary of the official catalogue of 

 the exhibits, those on related subjects have, so far as 

 possible, been grouped together. 



Mr. H. R. A. MallocI:, F.R..H.: Instrument for record- 

 ing by photography rapid changes of pressure in the air. 

 such, for e.xample, as are caused by the wave produced by 

 an explosion. — The Director of the .Meteorological Office : 

 Model of the neighbourhood of the winter quarters of the 

 National .\ntarclic ship Discovery, 1902-4. — Dr. W. }. S. 

 Lockyer : Cloud studies. The pictures exhibited represent 

 some of the first results secured in attempting to photo- 

 graph cloud forms during the p.-ist year. After some trials 

 it was found that by the use of yellow screens (xio for 

 summer and xs for winter) and an orlho-process plate, 

 sufficient contrast was obtained without undue length of 

 exposure. No difficulty was experienced in photographing 

 either heavy " cumulus " cloud or very elevated " cirrus.'' 

 — Solar I'hysics Observatory, South Kensington : (i) Stellar 

 spectrograms. (n) Bellatrix. 

 (h) Rigel, (c) Sirius, (dj 

 6 L'rs^ Majoris, (c) Capella. 

 (2) Spectroheliograms. Two 

 series showing the develop- 

 ment of the large spot of 

 March {5-17), 1907. (31 Recent 

 photographs of British stone 

 circles, &c., in Cornwall. — 

 Cotnniander Chetivynd, R.N. : 

 Improved liquid compass. In 

 the compass exhibited the 

 diameter of the card is con- 

 siderably smaller than that of 

 the bowl, the proportion being 

 three-quarters, so that the 

 edge of the card is substan- 

 tially outside the influence of 

 that ring of damping fluid 

 which, on altering the ship's 

 course (or whilst turning the 

 compass bowl), adheres to and 

 is drawn round by the inner 

 surface of the bowl. The 

 edge of the card being so far 

 from the inner surface of the 

 bowl on which the lubber's 

 line is usually marked, a 

 special lubber's mark or 

 pointer is introduced project- 

 mg horizontally from the bowl 

 on a level with the card. 

 The extremity of this pointer, 

 filed to a fine point and being 

 in close proximity to the edge of the card, obviates 

 all possibility of error of parallax in reading the 

 course, without in any wav causing a disturbance of the 

 card.— .Ur. H. Cmiynghamc, C.B. : A detached gravity 

 escapement. The object of this escapement is to cause 

 the impulse on the pendulum to be given by means of a 

 light arm which falls by the action of gravity, and is. ^ 

 hence independent of the force of the train, and to provide i 

 that the release of the train that winds up the arm is 

 not derived from a blow bv the pendulum, but of the arm 

 itself. 



Prof. W. E. Dalhy : Working models, illustrating the 

 balancing of a two-cylinder gas engine and a locomotive. 

 — Prof. .1. G. .Ishcroft : Lecture table testing machine. — 

 Colonel R. E. Crornplon, R.E. : Crompton's measuring 

 machine, combining accuracy with rapidity in working. 

 With this measuring machine, which has been designed 

 for observing length differences due to the heat treatment 

 of specimens of steel, measurements of objects from i inch 

 to 6 inches long, not differing among themselves more 

 than a quarter of an inch, can be made and entered on 

 the test sheet at the rate of one per minute. The accuracy 

 obtainable is greater than i in 200,000. — Mr. S. G. Browiii 



