December o 



1 ' i: 



NATURE 



481 



>{ the same series, vvlikh dealt with the geology and 



node of occurrence of these materials, and thus com- 

 pletes the information on these important substances 



ilready published. The chemistry of the raw 

 materials and the chemical changes which they 

 undergo in order to fit them for use in the furnace 

 are discussed in some detail, and a number of com- 

 plete analyses, most of which have been made in the 

 Survey laboratory, are included. Much attention has 

 also been devoted to the microscopic examination of 

 the materials in their natise state, as f>repared for 

 use in the furnace and after such use. The volume 

 is, therefore, likely to be found extremely valuable 

 to all users of refractory materials, more particularly 

 to steel-makers, whose requirements have evidently 

 received special attention. 



TiiF. process of cold vulcani.sation of rubber in- 

 'inted by Mr. .S. J. Peachey, to which reference was 

 made in Natirk of July 15, p. 625, consists in treat. 

 ing the rubber alternately with sulphur dioxide and 

 hxdrogen sulphide. The gases are separately ab- 

 surbed by the rubber, and by interaction produce a 

 highly active form of sulphur which brings about 

 vulcanisation. The process obviates the use of 

 ■■ulphur chloride, and, since it takes place in the 

 ^ nld, renders possible the use of organic filling and 



''louring agents which are not affected by the two 

 biases, but would be decomposed in the ordinary 

 I>roccss. 



.^N excellent feature of a new catalogue received 

 from Mr. Cuthbert Andrews (47 Red I. ion Street, 

 W'.C. i) is a series of six coloured plates illus- 

 ■r.iting X-ray tubes in action. These illustrations, 



' sides being extremely gotxt technical productions, 

 •-hould be very instructive to those who desire to 

 familiarise themselves with the various appearances 



f X-ray tubes. There is, of course, still a wide field 

 ■ f utility in the gas-tube, and the various devices 

 <lesigned to overcome some of their vagaries are dealt 

 with in detail in this catalogue. Protective measures 

 in X-ray work are not lost sight of; the appliances 



■anufactured by .Mr. .\ndrews are given the rather 

 ippy name of "Prolex." 



The difficulty experienced by workers in damp 

 imates in maintaining the insulation of electrostatic 

 easuring instruments has, according to the July 

 >uc of the Journal of the Asiatic Society of Bengal, 

 I Prof. Jackson and Mr, A. T. Mukerjec to enclose 

 eir Dolezaiek electrometers in hermetically sealed 



iscs and to test the efficiencies of the desiccators in 



• immon use. They find that for reducing the rate 

 I leak from such an electrometer calcium chloride, 

 'idium. quicklime, an<l phosphorus (jentoxidc are 



\alu«-le>s, owing possibly to the chemical action 



Im iween them and the moisture they take up pro- 



iliicing ions which render the air conducting. Sul- 



huric acid boiled with a small quantity of ammonium 



iilphate, a.s recommended .for Kelvin electrometers, 



■id having a density of 1-84, corresponding to 95 per 



• nt. of pure acid, is the only desiccant thev have 

 ■und to be entirely suitable. If occasionally stirred 



lins its efTli ien< v for several weeks. 



.NO. 2667, VOL. ro6] 



The October issue of the Journal of the Franklin 

 Institute contains the address on optical glass given 

 by Dr. A. L. Day, the director of the geophysical 

 laboratory of the Carnegie Institution, and during the 

 war in charge of optical glass production, to the 

 physics and chemistry section of iJie institute in 

 .March last. In the course of the address Dr. Day 

 described the steps taken by the United States Govern- 

 ment to help the manufacturers to overcome the diffi- 

 culties of the manufacture of optical glass in sufficient 

 quantities to meet the demand produced by the war. 

 It was found that the manufacture was not beset 

 with mysteries as it had been represented to be, but 

 that it was a straightforward scientific problem 

 solvable bv the methods commonly used in attacking 

 problems of high precision. The results of the experi- 

 ence are all published, and are available for those who 

 wish to make the manufacture of optical glass a 

 permanent industry of the country. It is, however, 

 recognised that the demand will be small, and that 

 the industry may have to be subsidised by the Govern- 

 ment, or, if not, to depend on other lines for its 

 profits. 



Messrs. I'.vMuKhi.Li a.nd Kacki.n, Ltu., of 46 Hatton 

 Garden, London, E.C.i, have forwarded to us their 

 list of self-recording meteorological instruments. The 

 various forms of barographs afford ample choice to 

 satisfy the different uses for which these instruments 

 are required. The "dial barograph," which gives the 

 face of the ordinary aneroid as well as the charted 

 record, adds much to the interest of the reading of 

 atmospheric pressure. With the new units of 

 measurement which are now becoming of such 

 general use it seeins desirable that the scale should 

 be given in millibars as well as in inches. Baro- 

 thermographs showing the records of pressure and 

 temperature an the same drum will be welcomed by 

 many. The Kdne> hygrograph seems an improvement 

 on the ordinary arrangement for securing an accurate 

 temperature and for reducing the sluggishness intro- 

 duced into some other forins of thermographs. Prices 

 are necessarily high in comparison with pre-war rates, 

 but the^ advance is not excessive. The firm has a long 

 record, since 1750, which is essentially an advantage 

 to a maker of all kinds of scientific instruments, as 

 many improvements are the more easily recognised. 



The presidential address of Mr. LI. B. .Atkinson 

 to the Institution of Electrical Engineers, delivered 

 on November 18, marked the cotnmcncenK-nt of the 

 jubilee year of the institution, which was founded in 

 1871 as the Society of Telegraph Engineers, although 

 a previous society, called the Electrical Society of 

 London, had existed from 1X^7 to 1845. In review, 

 ing the progress achieved during the last half^^entury 

 the president traced the changi.-s in our conceptions of 

 electrical and other physical phenomena from Max- 

 well's original ideas to the modem electron theory 

 and the newer outlook revealed by the researches of 

 Einstein and others. The development of methods of 

 generation of electrical currents by me<hanical means 

 was followe<l from the discovery of the self-exciting 

 dynamo in i>^''7 i" thr 1 in;, turbo-attcrnators of 



