226' 



NATURE 



[January 4, 1894 



and the volunteer nuisance is scarcely known here even 

 by name. I can therefore only repeat that it is a very 

 risky enterprise for a young, inexperienced chemist to 

 come to England without a definite engagement, as so 

 often happens. The result, with very few exceptions, is 

 disillusionment, and many get into most unfortunate 

 positions through financial pressure. The outlook is 

 somewhat better for a chemist who has had experience 

 and practice in works. But even such will find 

 it infinitely more difficult to find posts in England 

 than it is either in Germany or Austria, and will do well 

 to go to England only when offered a definite appoint- 

 ment. The thorough scientific training and business 

 capacity of the German chemist is unreservedly recog- 

 nised by all unprejudiced judges in contradistinction to 

 that of his Enj^lish colleague. In carr>ing on routine 

 operations, the English chemist is doubtless as compe- 

 tent as the German chemist, even if he be not his supe- 

 rior, but in conducting and developing chemical indus- 

 tries on a scientific basis the latter is far in advance of 

 the former. 



" I need refer but briefly to the great chemical indus- 

 tries, as they are well enough known. Of these the first 

 to be mentioned is the soda industry, including that of 

 sulphuric acid and chlorine ; furthermore, tar-distilling, 

 dyeing, calico-printing, the manufacture of iron, steel, 

 copper, tin, and antimony, glass-making, the utilisation 

 of fatty matters, the Scotch parafifin industry, and the 

 manufacture of bichromate. These industries, excepting 

 glass-making, employ a considerable number of chemists, 

 although, in proportion to their output, not nearly so 

 many as the German works. This is especially the case 

 in dye works, calico-printing works, and in those dealing 

 with fatty matters, many of which carry on their manu- 

 facture without chemists, or only with the aid of very 

 imperfectly trained chemists, as every one here regards 

 himself as a full-blown chemist who, after a most 

 elementary preliminary training, has attended a 

 technical course during one, or at most, two years. 

 At least 80 per cent, of the chemists engaged 

 in the industries mentioned are Englishmen, the 

 remainder being either Germans or Swiss. I have 

 never met a French chemist here. With few exceptions 

 the condition of these industries during recent years 

 must be characterised as dull and even as bad in some 

 cases ; they therefore offer the chemist little prospect of 

 employment, and foreign capital is certainly not to be 

 invested in them with advantage. Only dye-v/orks and 

 those utilising fatty matters offer a prospect to the e.x- 

 perienced chemist, as these are both distinctly capable of 

 being improved in position. The helpless condition of 

 the English aniline colour works is peculiar, these having 

 been simply stifled by the German works, which have 

 developed vvith such giant strides. The English works 

 eke out a miserable existence, and altogether do not 

 employ as many chemists as are to be found in a similar 

 German works of the fifth or sixth rank. Fuchsine, 

 soluble blue, chrysoidine, Bismarck brown, and the few 

 naphthol colours unprotected by patents, are almost the 

 onlycolours manufactured. Not a singledyestuft"of import- 

 ance is made by any English firm alone, as scientific la- 

 boratories such as are a matter of course in every German 

 works exist here only in the most rudimentary form. Most 

 of the chemists engaged in English aniline colour works 

 are German (? ?), but the demand for chemists in these 

 works is very small. The erection of such a works in 

 England on the German model could only be achieved 

 by the large German firms engaged in this industry ; it is 

 another question whether it would pay. But the manu- 

 facture of pigments— of mineral coloursfjand lakes— is 

 certainly capable of development here. It is true there 

 are a number of such works, but these rarely employ a 

 chemist, and still more rarely one who has had a thorough 

 scientific training. Consequently, enormous quantities 



NO. 1262, VOL. 49] 



of lakes are imported, especially for printing oil-cloths 

 and carpets, which might equally well be manufactured 

 on the spot. The necessary capital would be not an 

 inconsiderable one, and may be estimated at, at least, 

 150,000 marks. Competent chemists in this branch can 

 probably count on easily finding employment here. 



" The manufacture of fine chemicals, which at present 

 are almost entirely imported from Germany and France, 

 is certainly capable of considerable development here. 

 Of these may be mentioned especially, tannin, tartar 

 emetic, pyrog^llol, oxalic acid, cyanide of potassium, and 

 most of the almost innumerable chemicals and prepara- 

 tions which are made use of in trade, and which are 

 either not made here at all, or in altogether insufficient 

 quantity and of poor quality. With reference to such 

 articles, in the case of which wages form a considerable 

 item in the cost of production, it is to be borne in mind 

 that English wages are on the average considerably higher 

 than German." 



THE EFFECTS OF LIGHT ON THE 

 ELECTRICAL DISCHARGE, 



"X^^HILE engaged on his classical experiments Hertz 

 ^ * noticed that the appearance of the discharge be- 

 tween the two terminals of the oscillator was greatly 

 changed upon the spark gap being illuminated by the 

 light coming from another spark. This change was not 

 due to an electrical action of the sparks, for it was equally 

 well produced by other sources of light, such as the 

 electric arc and burning magnesium, while all effect im- 

 mediately ceased on interposing a plate of glass. Since 

 the time when the above observations were made many ex- 

 perimentalists have investigated this subject and have ob- 

 tained rather divergent results. In most cases the source 

 of light employed has been the electric arc formed be- 

 tween carbon rods, though, with a view to increase the 

 proportion of ultra-violet rays emitted, Bi hat and 

 Blondlot used carbon rods with aluminium cores, while 

 Righi used a zinc rod for one terminal. Other observers 

 have used the spark of an induction coil passing between 

 terminals of copper, zinc, or aluminium. While Hertz 

 had only noticed that the illumination of the discharging 

 knobs increased the facility with which sparks passed, 

 Wiedemann, Ebert and Hallwachs found that it was only 

 when the negative terminal was illuminated that this 

 effect took place. More recent observations by Branly 

 have led to this view being modified, for he finds that on 

 illuminating a piece of zinc by the sparks of a large 

 induction coil produced between aluminium terminals, if 

 the source of light is sufficiently near to the plate, the loss 

 of charge is nearly as rapid for a positive as for a negative 

 charge. On increasing the distance between the spark 

 and the charged plate, the decrease in the rate of loss of 

 charge is much more rapid for positive than for negative 

 charges, and thus at some distance from the source of 

 light the negative charge is the only one which is ap- 

 preciably affected. Hence radiation of certain kinds in- 

 creases the rate at which a positively charged body loses 

 its charge, just as in the case of a negative charge, but 

 the rays which are active in the case of positive 

 electricity are absorbed by even a small thickness of air, 

 while those rays which are unabsorbed are still able to 

 accelerate the discharge of a negatively charged body. 



After having made a series of experiments in air at 

 ordinary pressures, Stoletow on the one hand, and Righi 

 on the other, have investigated the influence of pressure 

 on the phenomenon, and have both found that the effect 

 increases with a decrease of pressure, while Stoletow has 

 shown that if the rarefaction is carried to the extreme 

 limit there exists a pressure, after which the effect de- 

 creases as the pressure is further diminished. 



An experiment of Bichat's seems to show that the loss 



