NATURE 



[December 5, 1907 



uith which the present work does not compete in 

 fulness of treatment, the different parts of the sub- 

 ject being elaborated only so far as will be assimil- 

 able bv students. In dealing with matters that are 

 still unsettled, the author shows considerable judg- 

 ment, but he has perhaps a tendency to over-refine 

 the division and classification of phenomena, as, for 

 example, in discussing symbiosis, parasitism, and 

 fermentation. 



Short passages, in square brackets, have been in- 

 terpolated by the author here and there in this issue 

 with the intention of bringing the text up-to-date. 

 Special details may be thus indicated, but broader 

 advances can hardly be dealt with in this way ; never- 

 theless, the work is the most modern exposition of 

 the physiology of plants available in any language. 



F. F. B. 



LIQUID AND GASEOUS FUELS. 

 Liquid and Gaseous Fuels, and the Part They Play in 



Modern Poiver Production. By Prof. V. B. Lewes. 



Pp. xiv + 334. (London : A. Constable and Co., 



Ltd., 1907.) Price 6s. net. 

 XX^ITH the multiplication of institutions where the 

 teaching of applied science is made a leading 

 feature, there has sprung into existence quite a num- 

 ber of text-books which specially appeal to students of 

 this kind. Some of these works are both interesting 

 and useful, but it must be confessed that they one 

 and all seem rather to appeal to the type of mind 

 which is disinclined to attack any really difficult 

 problems. Text-books such as were published twenty 

 years ago, by men such as Rankin and Cotterill, 

 which endeavoured to get at the scientific principles 

 underlying the applications of applied science, seem, 

 with very few exceptions, to have gone out of date 

 and to have become replaced with more interesting 

 and better written books, dealing more or less 

 with the descriptive part of the subject which they 

 treat. Prof. Lewes very modestly states that he does 

 not wish to produce a work that shall, to any 

 extent, enter into detail, and his book is professedly 

 a sketch of the subject. This is to be regretted, as 

 wc feel sure that a chemist of such eminence could 

 have produced a \\ork which would have been of 

 great value, not only to the students, but to that large 

 class of engineers who wish to get information on 

 some of the difficult points in connection with both 

 liquid and gaseous fuels. 



The chapters on combustion deal wholly with burn- 

 ing at ordinary pressures, and are both clear and 

 accurate. It is unfortunate that the scope of the 

 work does not allow Prof. Lewes to allude to some of 

 the phenomena of burning under pressure, a subject 

 of enormous importance, and one of which very little 

 is known. 



The description of the various forms of solid fuels, 

 together with the determination of their calorimetric 

 values, is well done, but we should have expected to 

 find something said about the discrepancy which 

 almost always occurs when using the Junker calori- 

 meter with gas and air, which has not been completely 

 saturated, as this affects the quantity of condensed 

 NO. 1988, VOL. 77] 



water that has to be measured in order to obtain 

 the lower value. 



There is a great deal of useful information on the 

 subject of liquid fuels; the arrangement of the hydro- 

 carbons contained in these fuels is very well brought 

 out, and no student can read through this chapter 

 without acquiring a good idea of the various forms 

 of liquid fuels derived from a common base.. 



The manufacture of coal-gas is, of course, of very 

 considerable interest. There is nothing very novel, 

 nor, should we say, of much service to the average 

 student, unless, indeed, he is proposing to become a 

 gas engineer. 



There is an excellent description of the various 

 methods of making water-gas, which at one time 

 it was anticipated would play a very considerable part 

 in the application of cheap gas for both heating 

 and power purposes, and is very largely used for 

 certain work. The large percentage of carbon 

 monoxide which it contains has caused it to be looked 

 upon with suspicion, except for the purpose of car- 

 buretted water-gas for use in coal-gas mains, and it 

 is probable that very little water-gas is used for any 

 other purpose, although, probably, this gas would be 

 very much more used if it were possible to obtain a 

 reduction in the standard now insisted upon as regards 

 the illuminating value of gas. 



The description of the producers proper is not so 

 full as the merits of these producers would entitle 

 them to. The suction producer is alluded to, but not 

 described to any great length, and in considering the 

 bituminous producers Prof. Lewes appears to con- 

 sider that it is essential in bituminous plants to re- 

 cover the ammonia. This is, of course, a mistake. 

 There are a large number of bituminous plants 

 running which do not recover the ammonia, and 

 which are perfectly satisfactory. Indeed, it is doubt- 

 ful whether in the method of using excess steam in 

 order to prevent the destruction of ammonia the value 

 of the bituminous plant is not brought down, as a 

 much better gas can be made w-hen the steam is cut 

 down to the lowest amount which can be used to 

 prevent clinkering. 



The last chapter, which deals with the fuel of the 

 future, is certainly the most interesting of the whole 

 work, and it points out very clearly that when the 

 existing supplies of fuel become limited, we shall 

 have to fall back upon alcohol, produced from vege- 

 tation of some sort or another, which may be made 

 almost inexhaustible. There is no doubt that this is 

 quite correct, and it is very much to be regretted that 

 at present no experiments on alcohol on any scale can 

 be made, owing to the restrictions which our fiscal 

 conditions impose, and we presume that owing to 

 this, the work will be carried out in some other 

 country where the Government is more sympathetic 

 towards scientific research. 



There is one point which Prof. Lewes appears to 

 have overlooked. He considers that the alcohol will 

 be either manufactured from potato starch or saw- 

 dust. There seems no reason to doubt that when the 

 question becomes urgent some highly-specialised plant 

 will have been brought into existence for the sole 



