February 17, 19 10] 



NA TURE 



467 



platinum resistance scale standardised at o°, ioo°, and at 

 the boiling point of sulphur, taken as 444-70° C, agree 

 with temperatures on the gas thermometer scale in the 

 interval 0° to 1100° C. within the limits of experimental 

 error of the latter scale. With impure platinum, for which 

 the constant S of Prof. Callendar's interpolation formula 

 differs from 1-5, the value of S has to be taken as increas- 

 ing with temperature by an amount which increases wiih 

 the degree of impurity before agreement with the gas scale 

 can be secured. With the pure palladium thermometer even 

 this is not sufficient. In neither case is the interpolation 

 formula proposed by Mr. J. D. H. Dickson found suitable. 

 High temperature appears to render the impure platinum 

 purer, possibly by evaporating impurities, as, for example, 

 iridium. The authors consider it desirable that thermo- 

 meters should be standardised at a fourth point in addition 

 to the three mentioned above, and suggest that the freezing 

 points of metals, even when only commercially pure, are 

 now known with sufficient accuracy, and are so easily 

 reproduced, that they furnish convenient fixed temperatures. 

 They give the following figures for the freezing points : — 

 tin, 231-92°; cadmium, 321-01°; lead, 327-43°; zinc, 

 4:9-37° ; antimony, 630-71° ; aluminium, 6580° ; silver, 

 960-9° ; copper, 1083-0° ; the 72 per cent, silver, 28 per 

 cent, copper eiffectic, 779-20°. 



H.M.S. Collingwood, the latest of our Dreadnought 

 battleships, has just completed her official steam, gunnery, 

 and torpedo trials, a brief account of which appears in the 

 Engineer for February 11. The Collingwood is the sixth 

 ship of her class floated, and was launched from Devon- 

 port Dockyard on November 7, 1908. The machinery is 

 of the Parsons turbine type, and there are two complete 

 sets, each set comprising one high-pressure ahead and 

 one high-pressure astern turbine ; one low-pressure ahead 

 turbine, in which is incorporated one low-pressure astern 

 turbine and one cruising turbine. The boilers are of the 

 latest improved large-tube Yarrow type, adapted for either 

 coal or oil fuel. During the speed trials the powers 

 specified were easily exceeded, and although the sea was 

 very rough while the battleship was run over the measured 

 mile at Polperro, the designed speed of 21 knots and the 

 specified shaft-horse-power of 24,500 was realised. Other 

 trials included 30-hour runs at 20 and 70 per cent, of 

 the full power, and eight hours at full power. The 

 machinery was constructed by Messrs. R. and W. Haw- 

 thorn Leslie and Co., Ltd., the order having been promptly 

 executed despite seven months' lost time during the 

 engineers' strike on the north-east coast. 



The first part of a general description of the engineer- 

 ing and constructional features of the Panama Canal, by 

 Mr. G. W. Goethals, chairman and chief engineer of the 

 Isthmian Canal Commission, appears in Engineering for 

 February 11. Among other interesting items, we learn 

 that dynamite is used for blasting, as excessive moisture 

 and water in the holes prevent the use of blasting powder. 

 An average of 1,000,000 lb. of dynamite per month is con- 

 sumed for the entire work, and the number of accidents 

 has been relatively small, although, owing to the number 

 of men in contracted areas, the casualties have been great. 

 Premature explosions, attributable to concussion during 

 loading, led to the substitution of pine-rammers for those 

 of lignum vitae. Temperature tests are made prior to load- 

 ing, as in some cases high temperatures exist in the holes. 

 Unexploded charges, subsequently dug out by steam 

 shovels, led to laying wires direct from electric-lighting 

 plants to the cut in substitution for the ordinary magneto- 

 electric machines operated by hand. The fuses are con- 

 NO. 2103, VOL. 82] 



nected in parallel in lieu of in series, failures often occur- 

 ring in the latter case, none in the former. No holes are 

 now loaded which cannot be fired the same day, a precau- 

 tion necessitated by the premature explosion of 22 tons 

 of 45 per cent, dynamite at Bas Obispo, probably owing 

 to some of the nitroglycerine having been liberated and' 

 exploded by concussion by a dobie shot in the vicinity. 

 Accidents have occurred during electric storms, and the 

 only possible precaution is now taken by stopping work. 



The evidence given at the Board of Trade inquiry into 

 the Stoat's Nest accident on the London, Brighton and 

 South Coast Railway shows that the left-hand leading 

 wheel of the coach which left the metals had been displaced 

 from its true position on the axle by about one inch. This 

 would be quite sufficient to cause an accident if the wheel 

 had previously shifted, and there is reason to believe that 

 this was the case, as the signalman had seen sparks flying 

 from the bogie frame near this wheel before the accident 

 occurred. Commenting on the evidence. Engineering for 

 February 4 points out that in many cases too much reliance 

 is put on the men in charge of the work of pressing wheels 

 on to the axles. A great deal of care is taken by the 

 railway companies, and only experienced men are chosen 

 for this work ; but the foremen cannot witness every opera- 

 tion, and there may be a tendency for workmen to pass 

 wheels which have been pressed on at figures barely reach- 

 ing the required limit. The pressure used in the case of 

 the wheel above mentioned was stated in evidence as sixty 

 toris. It is of interest to note that, at the Horwich works 

 of the Lancashire and Yorkshire Railway, an autographic 

 record is drawn by the press during each operation. Such 

 a record is invaluable as a check on the workmen, and 

 enables the foreman to deal promptly with cases of poor 

 work before the wheels leave the shop. The Engineer for 

 February 4, commenting on the accident, says that facing 

 points as now constructed are not dangerous, and that 

 diamond crossings are a source of danger. It is suggested 

 that the accident may have been caused by the wheel, 

 which was wide to gauge, striking the diamond crossing 

 which exists at the place where the accident occurred. 



Prof. W. H. Hussey contributes to the January Bulletin 

 of the American Mathematical Society tables of Galois 

 fields of order less than 1000. 



In the Rendiconto of the Naples Academy (3), xv., 3, 4, 

 Dr. Paolo Rossi discusses the nature of the secondary 

 radiations of X-rays and their dependence on the substance 

 which emits them. A property is referred to, analogous ii> 

 some respects to Stokes's law of fluorescence. 



Messrs. Hoepli, of Milan, have issued the fifth and 

 last volume of Brioschi's collected mathematical works, at 

 the price of 30 francs. This volume contains papers con- 

 tributed to French, German, and English mathematical and 

 scientific journals. 



Messrs. John Wheldon and Co., of 38 Great Queers 

 Street, Kingsway, London, have issued a classified entomo- 

 logical catalogue, comprising some 1400 books and papers 

 they have on sale. We notice that the list includes some 

 recent purchases and selections from various entomological 

 libraries. 



The ten numbers of the " Bulletin of Miscellaneous 

 Information," issued during 1909 from the Royal Botanic 

 Gardens, Kew, and noticed already from time to time in 

 Nature, have been published in volume form. Like other 

 Government publications, the book may be obtained, 

 directly or through any bookseller, from Messrs. Wyman 

 and Sons, Ltd., Fetter Lane, London. Its price is 3s. 6d. 



