5o6 



NA TURE 



[September 13, 1906 



tional needs of the young men and women of South London 

 are well provided for. The object of the classes is to 

 provide sound instruction and to promote industrial skill 

 and general knowledge. It is interesting to note that the 

 trade classes are intended especially and only for those 

 who are engaged in the several trades. Among such 

 classes may be mentioned as typical those for motor 

 drivers and repairers, motor engineers and designers, 

 sanitary inspectors, men engaged in electrical and building 

 industries, and bakers and confectioners. Special attention 

 is paid also to the technical education of women, for whom 

 a variety of trade classes has been arranged. Women are 

 trained for home duties in a special department, and 

 prominence is given to the scientific principles upon which 

 successful domestic practices depend. The arrangements 

 made for the coming winter are of a very complete 

 character. 



In the opening pages of the new calendar of the Uni- 

 versity College Hospital Medical School is an explanatory 

 statement of the new arrangements for medical education 

 consequent upon the formation by the University of London 

 of university centres for instruction. Under these arrange- 

 ments a student will enter one of the university centres 

 for the preliminary and intermediate medical studies, and 

 will then complete his career at the Hospital Medical 

 School, the whole of the energies and resources of which 

 will be devoted to a development of the medical studies 

 proper. The calendar contains an engraving of the new 

 buildings of University College Hospital, provided by the 

 generosity of the late Sir Blundell Maple, which will be 

 opened formally by H.R.H. the Duke of Connaught on 

 November 6. Another engraving shows an elevation of 

 the new medical school buildings erected through the 

 munificence of Sir Donald Currie. These buildings are 

 being specially constructed with laboratories and research 

 rooms for medicine, surgery, pathology, and other depart- 

 ments. 



A COMPREHENSIVE resolution referring to education was 

 .idopted last week at the Trade Union Congress at Liverpool. 

 .\mong the points accepted by the congress as essential to 

 a sound educational system are the following : — (i) scien- 

 tific physical education with medical inspection and records 

 of the physical development of all children attending State 

 schools, and skilled medical attendance for any child re- 

 quiring same ; (2) a national system of education under full 

 popular control, free and secular, from the primary school 

 to the university ; (3) secondary and technical education 

 to be an essential part of every child's education, and to 

 be secured by such an extension of the scholarship system 

 as will place a maintenance scholarship within the reach 

 of every child, and thus make it possible for all children 

 to be full-time day pupils up to the age of sixteen ; (4) the 

 best intellectual and technical training to be provided for 

 the teachers of the children ; (5) the cost of education to 

 he met by grants from the Imperial Exchequer, and by 

 the restoration of misappropriated educational endow- 

 ments. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, June 28. — " Researches on Explosives." 

 Part iv. By Sir A. Noble, Bart., K.C.B., F.R.S. 



In part iii. of his " Researches on Explosives " the 

 author gave the results of a very extensive series of experi- 

 ments on certain explosives, which were, first, the cordite 

 of the Service, known as Mark 1. ; second, the modified 

 cordite, known as M.D. ; and third, the nitrocellulose, 

 known as Rottweil R.R. The experiments made extended, 

 for all the above explosives, from densities of 005 to 0-45 or 

 0-50, and pressures of from 2-75 tons per square inch 

 (419 atmospheres) to pressures of 60 tons per square inch 

 (9145 atmospheres). 



In the present paper full details are given of three other 

 explosives, and comparisons are made between them and 

 the explosives which have been so much experimented with 

 in this country. If reference be made to the tables, which 

 cannot be given in this abstract, it will be seen how wide 

 are the differences between the explosives, not only in the 

 absolute volumes of the several gases, but in the variations 

 with reference to the densities at which thev were fired. 



Thus, for example, comparing Norwegian 165 and Italian 

 ballistites, while in the former the carbon monoxide com- 

 mences at the density 0-05, with a percentage volume of 

 3f5.-;, falling at a density of 0-45 to 22 per cent., the carbon 

 dioxide commences with 13-3 per cent., rising rapidly to 

 31 per cent. In the latter e.xplosive the CO commences 

 at 20-5 per cent., and falls slowly to 15 per cent., while 

 the CO, commences a little above 26 per cent., rising 

 also comparatively slowly to nearly 34 per cent. 



But there are, in these two explosives, other remarkable 

 differences. Thus, in the Italian ballistite, at a density 

 of 0'05, the volume of methane CHj is a mere trace, about 

 0-02 per cent., and it remains very much lower than is the 

 case with any other explosive, being only 1-9 per cent, at 

 the density of 0-45. \Vith the Norwegian, on the other 

 hand, the CH,, although the volume at commencement is 

 only 004 per cent., is, at 0-45 density, 11 per cent. 



Again, as might be expected, from the large quantity of 

 CH., found in the case of the Norwegian ballistite, the 

 volume of hydrogen falls from more than 20 per cent, to 

 about 9 per cent. ; in the Italian the H rises from about 

 8 per cent, to about 10 per cent., falling slightly at higher 

 densities. 



In both explosives the N is practically constant at about 

 12 and 16 per cent, respectively, but there is a very great 

 difference as regards the H,0. In the Norwegian the H,,0 

 is constant at 14 per cent., there being no greater differ- 

 ence than might be expected from errors of observation, 

 while, in the Italian, the H,0, which commences at 

 density O'Os, with a volume of 29 per cent., falls at a 

 density of 0-45 to about 24 per cent. No other explosive 

 approaches the Italian ballistite in respect to the large 

 volume of aqueous vapour formed, especially at low 

 densities. 



In the tables are given the volumes in cubic centimetres 

 per gram ot the permanent and total gases, and curves 

 have been drawn representing for the six explosives the 

 observations of these volumes. In the case of five of the 

 explosives there is, with increasing density, a very consider- 

 able decrease in volume, but with the Italian ballistite, 

 throughout the range of the experiments, there is hardly 

 any change. Curves representing these volumes are con- 

 cave to the axis of abscissje. 



In the tables are shown the units of heat, both for 

 water fluid and water gaseous. Curves have also been 

 drawn for the units of heat (water gaseous) ; the curves in 

 this instance are all convex to the axis of abscissse, and it 

 may be noted that, where the volume of gas per gram is 

 large, the units of heat are low, and that, where the 

 volumes of gas are rapidly decreasing, the curves represent- 

 ing the amount of heat developed show a rapid increase. 



The next point to be considered is, the data being as 

 is shown in the tables, what temperature are we to assign 

 to that generated by the explosion? With the view of 

 studying the question, the author resorted to two 

 methods : — (i) Knowing with very considerable accuracy the 

 units of heat (water gaseous) generated by the explosion, 

 and having determined approximately the specific heat of 

 the gases, the temperature of explosion should be given by 

 the equation 



gram units of heat , , 



specific heat 



(2) Knowing also with considerable accuracy the pressure 

 at any given density, and knowing the pressure p„ when 

 the volume of gas generated is reduced to the temperature 

 of 0° C, and a pressure of 760 mm. of mercury, the 

 temperature is given by the equation 



0-00367 /„ 



(2) 



NO. 1924, VOL. 74] 



With reference to equation (i), the specific heat of CO^ 

 is a very important factor in this determination, and the 

 recent researches of Messrs. Holborn and Austin upon the 

 specific heat of gases at constant pressure at high tempera- 

 tures having apparently shown that the specific heats given 

 by Mallard and Le Chatelier for temperatures above 100° C. 

 are considerably too high, the author has taken the figures 

 given by the former physicists, which, it may be remarked, 

 up to temperatures of 800° C, are confirmed by Langen. 



