August 2, 19 17] 



NATURE 



45. 



this increase beincf, however, by no means 

 uniform all round. There have been considerable de- 

 creases in the production of such building materials 

 as clay, lime, sand, etc., whilst the quantities of all 

 the metals produced, with the sole exception of silver, 

 show marked increases; the increase in the output 

 of pig-iron produced from Canadian ores amounts to 

 nearly 63 per cent., and in the output of copper to 

 33 per cent. Of non-metallic minerals, ooal is still 

 by far the most important, its value being returned 

 as 2342 per cent, of the total value of all Canadian 

 mineral products; the output, practically 135 million 

 (short) tons, shows a trifling falling off from the out- 

 put in 1914; this decrease appears to be entirely due 

 to shortage of labour. In this connection, attention 

 mav be directed to Bulletin No. 14, recently issued 

 by the department, on "The Coalfields and Coal In- 

 dustry of Eastern Canada," which gives an excellent 

 account — historical, geological, technical, and econ- 

 omic — of the coalfields of the maritime provinces. 

 The impK)rtant part that these coalfields are playing 

 in the industrial development of Canada is well 

 brought out in this useful monograph. 



In the Christiania Forhand, 1907, Prof. C. Stormer 

 gave a theoretical discussion of the motion of an 

 electron round a centre of force from which a mag- 

 netic and also an electrostatic field originated, a 

 problem which has also been treated by Principal 

 Hicks in the Proc. Royal Soc. (vol. xci.. A). In a 

 publication recently received, '* Sur un Probleme relatif 

 au mouvement des Corpuscules Electriques dans 

 I'espace cosmique" (Christiania : Videnskabssel Rabets 

 Skrifter, 1917), Prof. Stormer gives a series of numerical 

 calculations of orbits about a magneto-electric centre. 

 Obviously orbits of given energy must be confined to 

 surfaces of revolution about the magnetic axis. Dia- 

 grams and photographs of these surfaces are given 

 in profusion, the latter being obtained by photograph- 

 ing the rapid rotation of a whitened wire bent to the 

 shape of the generating curve. The title of the 

 memoir is somewhat misleading, for it is purely 

 mathematical, and there is no discussion of the bear- 

 ing of the results obtained upon the problem of the 

 motion of electrons in cosmic space. 



The paper on dielectric losses in insulating mate- 

 rials read before the American Institute of Electrical 

 Engineers in March by Mr. C. E. Skinner, of the 

 research department of the Westinghouse Company, 

 is published in full in the June number of the Journal 

 of the Franklin Institute. The material is tested 

 either in sheets or when built into the transformer 

 or alternator in which it is used. It is subjected to 

 an alternating voltage up to 50 kilovolts at a fre- 

 quency of 25 to 60. The power absorbed by the in- 

 sulator is measured by the quadrant electrometer watt- 

 meter method, the difference of potential between the 

 needle and quadrants of the electrometer depending 

 I on the voltage applied to the specimen, while the 

 j difference of potential between the pairs of quadrants 

 I is proportional to the current taken by the specimen. 

 I The curves for the various materials given in the 

 paper show that the power absorbed by the dielectric 

 is equal to the product of a constant into the nth 

 j power of the voltage applied. The value of n is not 

 given, but from the curves it appears for a given 

 I material to be nearly independent of the temperature 

 ' and of the frequency of the alternations, while the 

 nstant depends on both these quantities. 



I A PAPER on "The Action of Chemical and Physical 



j Agents on some Types of Scientific Glassware," by 



J. D. Cauwood, S. English, and W. E. S. Turner, 



\\ as read at the meeting of the Society of Glass Tech- 



NO. 2492, VOL. 99] 



nology held in Manchester on July 25. Soon after the 

 outbreak of war, chiefly owing to the insistent de- 

 mands of the Sheffield steel works' chemists, steps 

 were taken to promote the manufacture of high-grade 

 chemical ware in this country. How well the glass 

 manufacturers have risen to the occasion is shown b\' 

 the results given in the paper, for it appears that 

 glasses have been produced as good as, if not better, in 

 some respects, than, the best German glasses. The 

 method employed in the research had been to subject 

 Jena glass, five new British resistance glasses, and a 

 few chemical glasses made in Allied and neutral coun- 

 tries to a series of fourteen definite tests. In even.' 

 test applied the British glasses compared most favour- 

 ably with Jena glass, in some of the tests even sur- 

 passing it. 



Prof. J. Sebelien, of the Norwegian Agricultural 

 High School of Aas, has recently {Tidsskr, for Kemi, 

 Farmaci og Terapi, Nos. 5-8, 1917) published the re- 

 sults of a comparative examination of chemical glass^ 

 and porcelain ware and of filter paper from various 

 sources. - It would appear that owing to the war the 

 former Grerman monopoly is also threatened in neutral 

 laboratories. The Swedish glass of the Limmared 

 works compares favourably with Jena glass as regards 

 resistance to chemical reagents, particularly to potass- 

 ium hydroxide, which dissolves considerable quantities 

 of silica and of boric acid from Jena glass. The 

 laboratory porcelain of the Royal Porcelain Works at 

 Worcester was found to be quite as good as that of 

 the Berlin factory ; both these ars superior to the 

 Haldenwanger and the Bayeux products. The author 

 confirms the findings of the National Physical Labora- 

 tory with regard to the Worcester porcelain, which is 

 slightly less resistant to heat changes than that manu- 

 factured in Berlin, and slightly more resistant to 

 chemical reagents. Munktell's Swedish filter paper 

 was found superior to others tried as regards low ash 

 content and uniformity, some of the German kinds 

 showing considerable variations. The Whatman 

 papers compare favourably with the German makes, 

 the excellence of which is by no means so exclusive 

 as the makers would suggest. With respect to chem- 

 icals, Norway appears to have been almost absolutely 

 dependent on imports from Germany, but some sub- 

 stances are now being manufactured. The author 

 points out that the war has taught Great Britain to 

 free herself from Germany in the matter of pure 

 laboratory reagents, and expects that after the war 

 these will be obtainable in his country at the same 

 prices as the German products. 



Engineering for July 27 contains an account, with 

 drawings, of the wooden ships which are being built 

 in the United States in order to compensate for the 

 war losses in the mercantile marine without making 

 great demands on steel, which is required in ever- 

 increasing quantities for war munitions. The specifi- 

 cations for the ships illustrated were prepared by Mr. 

 Theodore Ferris, the naval architect of the United 

 States Government Shipping Board. The vessels are 

 of the single-deck type, 281 ft. 6 in. long, 46 ft. beam, 

 and 26 ft. moulded depth. The total estimated dead- 

 weight is 3500 (long) tons; the sea speed, loaded, will 

 be 10 knots, and two 3-in. guns will be carried. Four 

 caulked watertight wooden bulkheads extend to the 

 upper deck, forming two cargo holds and the machinerv 

 space. The. propelling machinery may consist of one 

 triple-expansion engine, or twin-screw reciprocating 

 engines, or geared turbines, subject to the approval of 

 the owners. The timber used in the construction of 

 the vessels may be either dense southern yellow pine 

 or Douglas fir, with stern-post, rudder-post, etc., of 

 white oak. Wood knees will be of hackmatack or oak. 

 Joiner sheathing and decks will be of cypress. 



