April, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



415 



which islands and continents become stocked with their 

 respective floras. And four years later, the same kind 

 of investigation was continued on Keeling Atoll, and during 

 a journey along the coast of Java. This, however, failed 

 to satisfy his idea of thoroughness ; and in consequence the 

 years from 1S90 to iSc|6 were largely devoted to a study of 

 the constitution of the British flora from the standpoint of 

 dispersal by water. But the completion of the work was 

 accomplished during a second residence in the Pacific, 

 from 1896 to 1899, when Dr. Guppy spent a large amount 

 of time on Vansea Leva, in the Fiji group, the geology 

 of which forms the subject of the predecessor to the present 

 handsome volume. That the author is fully competent to 

 discuss such a difficult subject as plant-dispersal, must 

 accordingly be self-evident ; and it is probable that he may 

 be regaraed as one of the greatest living authorities on 

 this branch of botany. To follow his arguments is quite 

 impossible within our limits ; and it can only be mentioned 

 that Dr. Guppy attaches prime importance to the buoyant 

 character of seeds and fruits as a factor in plant-dispersal. 

 So much so, indeed, is this the case, that if plants be divided 

 into two groups, the one with buoyant, and the other with 

 non-buoyant fruits or seeds, it will be found that nearly all 

 the members of the former are concentrated near the coast. 

 Insects, bats, and birds have, however, likewise had a 

 large share in the dispersal of seeds. Although much of 

 the work is necessarily technical, a large portion is very 

 interesting reading; and the whole forms a mine of infor- 

 mation oil a lascinating subject. 



Methodes de Calcul tiraphique en usage a I'Observatoire 

 Royal de Lisbonne. Far Frederico Oom (Lisbon Imprim- 

 ene Nationale, 1905 ; pp. 25, with four plates). — The Ob- 

 servat(jry of Lisbon is to be congratulated on the success 

 with which it has facilitated a number of different calcula- 

 tions by the use of diagrams, and by the construction of 

 special forms of slide rules. We are told that the methods 

 here described are all due in the first instance to Vice- 

 Admiral Campos Rodrigues, the director of the Observa- 

 tory. Among the calculations performed by diagrams, we 

 note the corrections for deviation and level error in obser\a- 

 tions with a transit circle, corrections for temperature, cal- 

 culations of precession. In all these calculations, the or- 

 dinary " graphs " of our school courses would be insuffi- 

 cient, as the quantities involve .several variables ; the 

 methods are, in fact, more analogous to those described 

 by M. d'Ocagne, under the title of Nomography. The 

 slide rules are still more interesting. One is used for con- 

 version of solar into sidereal time, and conversely ; another, 

 in which the graduations represent reciprocals instead of 

 logarithms (as on the ordinary scale), serves for calculations 

 such as those connected with conjugate foci of a lens ; 

 another, graduated in squares, serves lo find the sum of 

 several squares, a calculation frequently required in the 

 theory ot errors, and so on. 



On Models of Cubic Surfaces. Jiy W . II. Hlythe, .M..\. 

 (Cambridge University Press, 1905; pp. lob). .Starting from 

 the well-known property that a cubic surface has twentv- 

 seven straight lines, real or imaginary, lying wholly on it, 

 Mr. BIythe started some time ago to construct models of 

 surfaces having these lines real. Finding, however, that 

 such models had also been " made in Germany," the author 

 has now collected in a handy form such properties and 

 methods as are useful in obtaining information as to the 

 forms and properties of cubic surfaces. There is no more 

 fascinating study than the forms and classification of 

 curves and surfaces, and the object of the investigations 

 described in this book is to do for surfaces of the third 

 degree what Newton did for curves of the third degree. 

 But the most noteworthy feature of the book is that it can 

 be read by anyone possessing a very limited knowledge of 

 mathematics, and it can therefore be recommended for the 

 interest of the subject to many readers for whom the 

 majority of treatises on higher geometry are sealed books. 



The Breeding Industry : Its Value to the Country, and 

 its Needs. l!v W. Ileajjc (Cambridge University Press, 

 igod; pp. .\ii I 154. Price 2s. 6d. net). For many years 

 past l\lr. Walter lleape has devoted himself with unre- 

 mitting allenlion .and energy to the study of all matters 

 (■(innecU'd with the breeding of domesticated aiiimals, .and 

 the many problems to which such a study must inevitably 



lead. His life's experience must be of the utmost value to 

 breeders, and it is therefore highly satisfactory to have the 

 results of his studies published in a concise form, and at 

 a price which will make them easily accessible to all. That 

 there was need for such a work cannot apparently be denied, 

 lor we are told that, despite the pre-eminence of this country 

 in cattle and horse breeding, science has never yet taken 

 her proper place in connection with breeding, if, indeed, she 

 can be said to have had a status of any kind. Indeed, the 

 author goes so far as to say that the breeding industry is 

 ihe greatest industry to w^hich scientific principles have never 

 yet been applied, and that the nation which first applies 

 science in this manner will reap solid advantage. May it 

 be hoped that Mr. Hcape's book will bring England first 

 into the field in this new departure. 



The Citizen: A study of the Individual and the Govern- 

 ment. By Nathaniel Southgate Shaler (London : Con- 

 stable and Co., 1905). — This book, by N. S. Shaler, Professor 

 of Geology in Harvard University, is written with the very 

 laudable object of impressing on his readers, and especially 

 .Americans, the duly of taking an active part in the municipal 

 and general government of their country. He commences 

 by tracing the origin of mankind, and, as we would expect 

 from a professor of geology who accepts the Darwinian 

 hypothesis, the author goes on to trace the beginnings of 

 government and then discusses the idea of liberty and the 

 limits of freedom, the duties of citizenship, wealth, educa- 

 tion, and civic government, religion, and the negro question. 

 We consider the chapter on wealth contains sound advice 

 to those who are inclined to extreme socialistic measures. 

 On one point we would join issue with him. As regards 

 Ihe proposal to have a bodyguard to the President, he says, 

 " It would establish a new principle that our magistrates 

 are to be set apart from our people, and are not fellow 

 citizens, to whom certain duties are for a time delegated. 

 Their risk is no greater than that of soldiers in 

 time of war." We think that the position of President is 

 more to be compared to that of a general, w-ho does not 

 needlessly expose himself to risk, as if he fall a campaign 

 may miscarry. .And as regards magistrates being set apart 

 from the people, is not this necessary if the people are to 

 respect the magistrates? We know the old proverb of 

 familiarity breeding contempt, and there is no doubt that 

 there is less respect for the courts of justice in America 

 than in any civilised country. 



.Messrs. John Wheldon & Co.'s special catalogue of books 

 and papers on Gardening and Horticulture has just been pub- 

 lished, and is of great interest and value to botanists and 

 horticulturists. The catalogue is especially strong in 

 antique books on floriculture, and includes examples of the 

 great Dutch horticulturist's works. 



In the new catalogues issued by Messrs. Isenthal and Co. 

 the new mercury vapour lamps hold a prominent place. 

 During the last few years the mercury vapour lamp, repre- 

 senting a much higher efliciency in the conversion of energy 

 into light than is possible in the case of incandescent lamps 

 or even of arc lamps, has passed out of the stage of a 

 laboratory experiment into practical use. Messrs. Isenthal 

 are now making them in three standard lengths of eighteen, 

 twenty-six, and thirty-eight inches respectively, so as fully 

 to utilise the varying standard voltages of from 100 to 250 

 volts. As the readers of " Knowledge " are well aware, the 

 light from mercury vapour lamps is conspicuously free from 

 red rays, and, being in appearance a bluish green light, im- 

 parts distinctive colours to all objects on which it falls. But 

 it fatigues the eye very little, and, owing to the great 

 diffusion of the rays arising from the length of the tubes in 

 which the light glows, casts no hard shadows. It is, there- 

 fore, very useful for technical purposes, such, for example, 

 as studio work, drawing, photochemical testing, or for 

 therapeutic purposes. The richness of the light in ultra- 

 violet rays lends to it specific purposes in other technical 

 applications. Messrs. Isenthal include in their catalogue a 

 nun'ber of new electric heating appliances to enable labora- 

 tories and factories to make use of the electric current for 

 the purposes of chemical, metallurgical, and physical work to 

 the fullest e.\tent. These are often extremely ingenious, and 

 show the increasing tendency to make use of electric energy 

 for he.iting purposes. 



