34 



NA TURE 



[July 8, 1922 



state of Yugoslavia, we have first a brief but clear 

 account of the geological structure of the region under 

 discussion ; it is greatly to be regretted that this part 

 of the work was not illustrated by a geological map of 

 some kind, even though it were only a small sketch 

 map, as this would have been extremely helpful for a 

 proper understanding of the somewhat complex geology. 

 The various mineral deposits are next described in 

 much detail, this constituting the principal and indeed 

 the most valuable portion of the work. Under the 

 heading of coal it is shown that true bituminous coal 

 is very scarce, but that there are considerable reserves 

 of lignites, which amount probably to about 1900 

 millions of tons, whilst the possible reserves are even 

 greater. With the exceptions of some of the smaller 

 beds of Liassic and Cretaceous coal in Serbia, all the 

 coals are of Tertiary age and are for the most part of 

 inferior quality, their calorific power lying usually 

 between 4000 and 5000 calories. They can, however, 

 be used successfully on railways, for steam raising and 

 for domestic purposes, but are not suited for metal- 

 lurgical operations or other work where high tempera- 

 tures are required. Apparently the coal resources of 

 the State would cover satisfactorily the great majority 

 of its requirements, were it not for the grave lack of 

 means of communication, which also has hindered in 

 no small degree the development of the various coal- 

 fields. 



There are quite a number of deposits of iron ore ; 

 according to Dr. Katzer, the Government geologist, 

 the more or less known reserves of iron ore amount to 

 some 22 million tons, of which 15 millions are limonite. 

 Mr. Wray is of opinion that " the total reserve tonnage 

 may safely be computed at 30 to 40 million metric 

 tons." The iron industry is, however, quite in- 

 significant ; there are a few small blast-furnaces, 

 chiefly in the Vares district, charcoal being apparently 

 the only fuel used ; one of these furnaces, situated at 

 Krapuli, 2 kilometres south of Vares, is said to have a 

 daily output of more than 100 tons of pig iron, probably 

 the largest ever obtained from a charcoal furnace. 

 Owing to the want of good coking coals and the defec- 

 tive means of transport, there seems at present little 

 probability that this industry can attain dimensions 

 of anv importance. 



There are well-known copper mines at Majdanpek, 

 which have been worked since Roman times ; the out- 

 put from 1870 to 1890 is stated to have totalled about 

 2500 tons of copper. Another important group of 

 mines is that of Bor, now being worked by a French 

 company ; the production is said to have gone up to 

 the high figure of 7575 metric tons of copper in the 

 year 1911-12. The famous quicksilver mines of Idria 

 have been worked ever since the fifteenth century, 

 NO. 2749, VOL. I 10] 



the annual output since 1900 having been of the order 

 of 500 tons. 



Among the other minerals that have been or are 

 being worked may be named iron pyrites, manganese 

 ore, chrome ore, antimony ore, gold, lead ore, zinc ore, 

 bauxite, meerschaum and rock-salt. 



It will be clear that Mr. Wray has done his work 

 extremely well and has collected a great bulk of very 

 valuable information. It is, however, to be regretted 

 that he did not submit his proofs for revision to some 

 competent metallurgist, as several blunders forming 

 serious blemishes in the report would in this way have 

 been detected. For instance, Mr. Wray states that 

 there are at Majdanpek " three furnaces of the 

 1 Knudsen ' type (Sulitelma and Co., Norway)," whereas 

 the Knudsen process is conducted in a special form of 

 converter, and was worked out by the inventor at the 

 well-known Sulitelma mines. Again, his description 

 of the " Majdan " furnaces, evidently a primitive form 

 of blast-furnace, is quite unintelligible ; he writes : 

 " The pig-iron came out in part with the scoriae, and 

 in part remained in the bottom of the furnace. The 

 latter product was much preferred, as by the continual 

 action of swiftly-moving hammers (driven by water- 

 power) it lent itself directly to treatment." It is 

 obvious that if this material was pig-iron, it could not 

 have been worked under the hammer, and we are left 

 in doubt whether it was malleable iron or steel, or 

 whether it really was pig-iron which was converted 

 into malleable iron in some kind of a finery ; either of 

 these might be the correct explanation, whereas the 

 statement as it stands is obviously incorrect. 



H. L. 



Hydraulics. 



Hydraulics with Working Tables. By E. S. Bellasis. 

 Third Edition. Pp. viii + 348. (London: Chapman 

 and Hall, Ltd., 1920.) Price 185. net. 



HYDRAULICS is largely an empirical science and 

 as experience accumulates it is to be expected 

 that the formulae expressing the flow of water in 

 particular conditions will be modified either in form or 

 by a change in the experimental coefficients. The 

 author of the book before us has had considerable 

 experience in the irrigation department of India, and 

 it might have been expected, therefore, that new data 

 confirming or modifying generally accepted formulas 

 would have been incorporated ; particularly additions 

 to knowledge in those cases in which the experimental 

 work has been small might have been forthcoming in this 

 work. We look in vain, however, for such new data ; 

 the author has been content to discuss certain principles, 

 to accept the generally accepted formulae and to illus- 



