September 8, 1904] 



NA TURE 



453 



development is o'ten hap-hazard, and the mental re- 

 volution required before Faraday's idea can be assimil- 

 ated fjenerallv proves troublesome to the student. 



The author's view, then, so far as we can gather, 

 is that the subject should be developed from Faraday's 

 standpoint. With this we are in complete sympathy. 

 But the problem of writing a text-book from a new 

 order of thought is no easy matter, and the first portion 

 of the volume is distinctly disappointing. There are 

 frequent relapses to the old method, the treatment is 

 somewhat laboured, and the result, so far from being 

 inspiring, is confusing and inconclusive. 



In the latter part of the volume the author treats of 

 electrical currents, and the fundamental laws are 

 developed without the introduction of the magnetic 

 properties. This is distinctly good, and, although not 

 quite new, will commend itself favourably to those 

 who take an interest in the philosophical and logical 

 jiresentation of the subject. 



We cannot help thinking that the author is some- 

 what misguided in pushing a hydrodynamical analogue 

 to the extent he does. It is difficult to reconcile the 

 suppositions that velocity corresponds to electrical 

 force, and pressure to electrical potential. Chapter x. 

 is devoted to " an extension of this hydrodynamical 

 picture." We are of opinion that when an analogy 

 becomes so troublesome that a chapter is required to 

 expound its additional artificial properties, it has ceased 

 to be of any assistance, and the sooner it is dropped 

 the better. 



Die Keimpflanzen der Gesneriaceen. By Dr. Karl 

 Fritsch. Pp. iv+i88. (Jena: G. Fischer, 1904.) 

 Price 4.50 marks. 

 The Gesneriaceae are generally familiar to horti- 

 culturists and others, since the order includes several 

 favourite greenhouse plants, to mention only 

 Ramondia, Saintpaulia, Achimenes, Streptocarpus, and 

 Sinningia, of which one species passes as Gloxinia. 

 The morphological peculiarities of these and other 

 less known genera are not so familiar, in fact, it has 

 been the object of Dr. Fritsch to find their correct 

 interpretation by the aid of cultivation and examination 

 of sufh seedlings as he was able to obtain. Some of 

 the principal morphological features are the tuber- 

 bearing plants of which Sinningia is a type; vegetative 

 scale-covered runners which propagate the plant, 

 characteristic of Achimenes and Kohleria (Isoloma) ; 

 and the unequal development of cotyledons which is 

 well known to cultivators of Streptocarpus Wendlandi. 

 The unequal development of the cotyledons is regarded 

 by the writer as a special case of anisophylly, for which 

 he proposes the term anisocotyly ; in this connection 

 there is a discussion of the views put forward by 

 Wiesner and Goebel on anisophylly, and it is shown 

 that some modification is required in order to explain 

 anisocotyly. A further irregularity in the case oi 

 Kliigia Zeylanica and some species of Streptocarpus 

 is the displacement of the cotyledons from the opposite 

 to an alternate position ; this is attributed to the 

 intercalary development of an internode between the 

 cotyledons, to which the name of mesocotvl is given. 



The scale-bearing runners have been variously de- 

 scribed ; they resemble bulbs in so far as the leaves 

 are swollen into food reservoirs, but they differ there- 

 from because the stem is elongated and also contains 

 reserve food material, and the swollen leaves may be 

 closely packed, when the runner resembles a pine cone, 

 or the leaves may be loosely arranged ; on this 

 account Dr. Fritsch prefers to call them bidbshoots 

 (Zwiebelsprosse), and he would include under this 

 designation the similar bcxiies which are found on 

 s[)c'cies of Epilobium, Oxalis, .Saxifraga, and Dicentra. 

 Dr. Fritsch confirms Lubbock's statement that the 

 NO. 18 I 9, VOL 70] 



tubers of Corytholoma (Gesnera of gardeners) and 

 Sinningia speciosa (Gloxinia) are produced by the 

 thickening of the hypocotyl, and adds that in the case 

 of Corytholoma cardinalis the epieotyl also takes part 

 in its formation. It is not possible to mention, much 

 less to pass in review, the various morphological details, 

 but enough has been said to show that the Gesneri- 

 acese, as an order, will repay careful study, and it 

 should be added that this account of the seedlings is 

 characterised by clearness and breadth of treatment, 

 and the German is simple enough to suit the veriest 

 tyro. 

 Das Leben iin WeltaU. By Dr. L. Zehnder. Pp. 125. 



(Leipzig : J. C. B. Mohr, 1904.) Price 2.50 marks. 

 Man and animals and plants all live, each in its degree. 

 Lower than these is matter itself. Does it live? Do 

 crystals live in their mother-liquid? In general, is the 

 universe itself a living thing? These are the questions 

 which a professor of physics of Munich attempts to 

 answer in this small volume. We learn that the 

 variations of matter, and those variations of plants 

 and animals which are taken as special evidence of 

 their vitality, are linked together in an unbroken chain. 

 On the other hand, an exception is made in respect to 

 the ultimate structure of the atom itself. In fact, a 

 well defined boundary is found to separate substances 

 of which inorganic bodies consist from substances 

 which are necessary for the formation of organic 

 bodies. 



We can by no means pretend to have followed all 

 the arguments put forward, even when they have purely 

 physical reference. Thus, the author concludes that 

 the cEther has an atomic structure merely on the 

 ground that, having decided that it is a substance, 

 there is neither sense in nor justification for attributing 

 to it any properties except those which other substances 

 possess. This dogmatic style of reasoning is 

 characteristic of the whole argument ; and it certainly 

 does not conduce to cotifidence when matters are dis- 

 cussed with which we are not so familiar. 



First Stage Steam. By J. W. Hayward, M.Sc. Pp. 



230. (London : W. B. Clive, University Tutorial 



Press, Ltd., 1904.) Price 2S. 

 Mr. Hayward is very happy in the treatment of his 

 subject in his " First Stage Steam," written to meet 

 the requirements of the examination of the Board of 

 Education at South Kensington. After a short intro- 

 ductory chapter on mensuration and squared paper 

 work, drawings of a simple horizontal steam engine 

 are given, and the functions of the various parts are 

 described in detail. This description occupies con- 

 siderable space, and at appropriate intervals is made 

 the occasion for the introduction of experiments and 

 calculations bearing on the subject. The Lancashire 

 boiler with its mountings is then well described, and 

 this leads naturally to the consideration of combustion 

 and the heat properties of steam. The reader is intro- 

 duced to these by simple and striking experiments 

 which he can make himself, and not until after this 

 has been done is the student informed of the results 

 of classical experiments on which heat calculations 

 of the steam engine are based. The writer then, 

 by the help of good illustrations, touches on the salient 

 points connected with the design and working of 

 modern locomotives, marine engines, interna! com- 

 bustion engines, and steam turbines. The reader is 

 left with the impression that there is very much in the 

 subject worthy of attentive study. A special feature 

 of the book is the encouragement given to quantitative 

 experimental work with simple apparatus which the 

 student can make and use himself. The book is not 

 free from slight defects, but is sure to give satisfaction 

 wherever used. 



