74 



NATURE 



[November 24, 1904 



tions orgranised expeditions to the native haunts of 

 the reindeer, where in one or two days more than loo 

 head were killed, and the greater number of them 

 allowed to lie and rot on the ground. The author 

 further gives a long list of birds which are threatened 

 with extinction unless something is done for their pre- 

 servation. The dangers to which Naturdenkmiiler are 

 exposed through the drainage and reclamation of lands, 

 utilisation of water-power, stone-quarries, exploitation 

 of moors for peat, &c., also the dangers of scientific 

 forestry, leading to the disappearance of all the virgin 

 forest, the uprooting of certain plants for commercial 

 purposes, trapping of birds for cages, and collecting 

 by ornithologists, are too numerous to mention in 

 detail. 



Around the ever-increasing centres of industry in 

 Germany the pollution of air and water is becoming 

 greater every day, with the result that plant and 

 animal communities, as well as the whole natural land- 

 scape, are undergoing a rapid and radical change, 

 which is necessarily accompanied by the disappearance 

 of rare and valuable Naturdenkmaler. The proposals 

 put forward by the author for their preservation occupy 

 the larger part of the book. Generally speaking, they 

 fall into three groups, viz. : — making a record of the 

 various Naturdenkmaler for the different States 

 throughout the Empire ; providing for their protection 

 in the various places ; and making them generally 

 known. In carrying out these proposals, it is 

 necessary that the Government should take an active 

 part by the passing of certain laws and allowing the 

 active cooperation of different officials in the various 

 departments. Also communities, societies, and private 

 individuals are called upon to lend their aid. The 

 various details in this proposed organisation for the 

 protection of nature's " monuments " seem quite 

 reasonable and eminently practical, but with laudable 

 modesty the author does not insist that they should 

 be accepted in their entirety. He puts them forward 

 more as a working basis, the details of which may be 

 subject to alteration from time to time as experience 

 and trial should suggest. He is, however, confident 

 that the time will come when the " monuments " of 

 nature will receive the same care and reverence as that 

 which has for long been bestowed upon the monu- 

 ments of early art and civilisation. 



PRINCIPLES OF FUEL COMBUSTION. 

 Smoke Prevention and Fuel Economy. By Wm. H. 

 Booth and John B. C. Kershaw. Pp. 194. 

 (London : Archibald Constable and Co., Ltd., 1904.) 

 Price 6s. net. 



IN the preface the authors state their object to be 

 the " bringing before the fuel using public the 

 principles of fuel combustion," more especially in re- 

 lation to the smoke question and the economic use 

 of fuel. They express their belief in the possibility of 

 burning bituminous coal perfectly, and that black 

 smoke is merely so much evidence of improper design. 

 " Both on humanitarian and economic grounds its sup- 

 pression is called for." 

 The general principles are clearly stated, and a brief 

 NO. 1830, VOL. 71] 



lent, ■ 

 ; the 1 



description of selected types of furnace arrangement, 

 stokers, &c., illustrated by good diagrams, makes the 

 whole a useful compilation. It cannot be claimed that 

 any addition has been made to our general knowledge 

 of the subject, for the importance of proper air supply, 

 perfect mixing of the gases and air for combustion, 

 the maintenance of a sufficiently high temperature for 

 unchecked combustion, and other points have long been 

 recognised in books dealing with boiler management. 

 Smoke, in fact, is possibly not so much the result of 

 ignorance as of conservatism and false economy. 



The l)ook contains many statements in reference to 

 water-tube boilers which few who have had practical 

 knowledge of their working will altogether agree with. 

 Thus " when moderately worked, some degree of 

 safety, or at least a danger much less than attached to 

 the discarded Howard boiler." Surely the rapid adop- 

 tion of boilers of this type in the large electric light- 

 ing and power stations, engineering works, &c., is a 

 sufficient answer to this. 



After a reference to the development and satisfactory 

 working of water-tube boilers with anthracite coals 

 in America, the authors refer to the same boilers being 

 erected in this country to burn bituminous coal, and 

 " being set exactly as in .America, the results have 

 been hopelesly bad, and the present smoke of London 

 is due to this boiler more than anything else " (p. 19). 

 It cannot be denied that the total sum paid in fines 

 for permitting smoke from steam plant of this type 

 has been fairly large, but does the total number of 

 water-tube boilers in London, many of them giving 

 grand results, bear any large proportion to boilers of 

 the old pattern, in spite of the rapid adoption of the 

 former in recent years? The statement we print in 

 italics is far too sweeping and altogether unjustified. 



As the authors point out, in many cases boilers, 

 presumably those in which the tubes are more nearly 

 horizontal than vertical, were often set too near the 

 fire, so that combustion was checked by the chilling 

 action of the tubes ; but this certainly does not apply 

 to another type of water-tube boiler in use where the 

 tubes are more nearly vertical than horizontal, for here 

 ample combustion space is provided. Several excellent 

 furnace arrangements are described and illustrated 

 which provide for the maintenance of a high tempera- 

 ture until combustion is complete with these boilers, 

 including the excellent one due to Mr. Miller. 

 Engineers, however, do not seem very favourably dis- 

 posed to much firebrick in the furnace, for it is not 

 easy to ensure its standing the high temperature for 

 any length of time, and water-tube boiler makers rather 

 fight shy of such arrangements owing to the excessive 

 heating of the lower tiers of tubes. 



Closely connected with this question is that of the 

 chain grate. As mentioned by the authors, this 

 practically fell into disuse until the advent of the water- 

 tube boiler resuscitated it, and yet we find the state- 

 ment " it (the chain grate) must fail under the straight 

 ascending flow of the usual setting of the water-tube 

 boiler." Everything turns on the usual setting. 

 There must be a number of unusual settings about, or 

 it is not easy to understand why this grate has been 

 so extensively adopted for these boilers. Certain it is 



