242 



NATURE 



[May 24, 19 1 7 



permissible to consider an inviscid fluid as the 

 limit of one in which vjrscosity has been 

 indefinitely reduced. No real fluid is known in 

 which the viscosity is small enougfh to admit 

 slipping- at a solid boundary, or, for that matter, 

 ^ any point in the fluid itself. 



There is need for a solution of the well-known 

 equations of motion for a viscous fluid, and great 

 possibilities appear to exist for the student who 

 has the courage to look the issue squarely in 

 the face. 



THE BRIQUETTING OF FUELS. 

 A Handbook of Briquetting. By Prof. G. 

 Franke. Translated by Fred. C. A. H. Lants- 

 berry. Vol. i., The Briquetting of Coals, 

 Brown Coals, and Other Fuels. Pp. xxviii + 

 631. (London: Charles Griffin and Co., Ltd., 

 1916.) Price 305. net. 



'T'HE work before us is a translation of the 

 -■- first part of Prof. Franke 's well-known and ■ 

 important work on briquetting. The entire work 

 deals with the whole subject of briquetting as 

 applied to a very wide range of materials, but the 

 first part, the translation of which has now been 

 issued, is confined to the briquetting of coal. 

 Although the full title is "The Briquetting of 

 Coals, Brown Coals, and other Fuels," the author 

 has practically confined himself to the two fuels 

 that he has specified ; nothing is said as to the 

 briquetting of peat, although this part of the 

 subject is far from unimportant, nor has the 

 briquetting of other materials, such as sawdust, 

 been dealt with. Within the limits in which he 

 has chosen to confine himself the author has, 

 however, done his work excellently well, and his 

 book may fairly be regarded as a standard treatise 

 on the subject. 



The book is practically divided into two parts, 

 the first dealing with the briquetting of bitu- 

 minous coal, the second with the briquetting of 

 lignite. The latter part is of less practical in- 

 terest to us in this country, merely because we 

 possess no deposits of lignite, with the exception 

 of the quite unimportant ones at Bovey Tracey, 

 in Devonshire, but is likely to be welcomed in 

 British colonies where lignite exists. The first 

 part, however, deals with a subject of most press- 

 ing importance, the urgency of which we have 

 barely begun to realise. It is quite well known 

 amongst coal-miners that millions of tons of small 

 coal of the non-coking kind, unsuitable, therefore, 

 for coke-making, are annually left behind in our 

 collieries and lost for ever to the nation, because 

 such coal is practically unsaleable, or at any rate 

 commands but a very low price so long as round 

 coal can be bought at a reasonable rate. Yet this 

 small coal is every bit as valuable as lump coal as 

 a source of heat, and could quite as readily be 

 turned to good account. . The thrifty Germans 

 have, however, learnt to utilise what we waste, 

 and hence it is that the manufacture of coal bri- 

 quettes, or patent fuel, as it is usually called here, 

 has made comparatively little progress in this 



NO. 2482, VOL. 99] 



country, whilst it has attained very important 

 dimensions in Germany. Thus, according to 

 Prof. Franke, the briquette production of Great 

 Britain in 1906 was i^ millions of tons, whereas 

 that of the German Empire (bituminous coalonly)i 

 was 3^ millions, whilst the respective produc- 

 tion of bituminous coal was 255 millions and 137 

 millions of tons. One reason is that our adher- 

 ence to old-fashioned, conservative methods- 

 stands in the way of the extended use of patent 

 fuel in this country; we export fully 90 per cent, 

 of the briquettes that we do produce, for whicb 

 reason the manufacture of patent fuel is confined 

 to our sea-board, and centres mainly in Soutb 

 Wales. On the other hand, some of the coals - 

 produced in our central coalfields, e.g. Notting- 

 ham and Derby, are exceedingly well suited to the 

 production of briquettes, and the small coal of 

 these districts ought to be thus utilised instead of 

 being wasted. 



Any colliery proprietor who is contemplating 

 the manufacture of briquettes will find in the 

 present work the fullest information as to every 

 detail and every aspect of the subject, the author 

 having performed his task in the most pains- 

 taking manner; perhaps the only fault that could 

 be found is that he is somewhat too meticulous. 

 Thus it scarcely seems necessary to describe, as 

 he does in detail, the construction and mode of 

 action of the ordinary Watts governor as applied 

 to a simple horizontal engine that is used to drive 

 a briquette press, but this fault is one on the 

 right side. His successive chapters in the first 

 part treating of bituminous coal are devoted to the 

 raw materials, namely, coal and binders, crushing, 

 mixing, drying, kneading and heating, pressing,, 

 loading and storage, design of complete plants, 

 and economies and statistics ; whilst the second 

 part deals with lignite briquettes in an equally 

 comprehensive fashion. 



Whilst, therefore, we have nothing but praise 

 for the manner in which the author has done his 

 work, we must regret that the same cannot be 

 said of the translator. This is, in fact, one of 

 the poorest translations that we have ever 

 seen. Two essential qualifications for producing 

 an acceptable translation are a thorough know- 

 ledge of the language of the original and a good 

 practical acquaintance with the subject-matter of 

 the work. The translator, however, does not 

 seem to understand German technical terms 

 or to know their English equivalents. The 

 result is a series of blunders, more or 

 less grotesque, some of them veritable 

 schoolboy "howlers." His ignorance of Ger- 

 man is shown on the very first page, where he- 

 translates Kohlensteine by "coal-stones," and 

 Kohlenziegel by "coal-bricks," whereas a mode- 

 rate knowledge of the language would have told 

 him that the proper words were " coal-bricks " 

 and "coal-tiles" respectively. He translates 

 Setzmaschine, i.e. "jig," by the utterly meaning- 

 less phrase "settling machine," and Montan- 

 wachs, literally " mine-wax " (a bitumen derived 

 from lignite), he calls " Montana wax " ! "Trans- 



