April 6, 191 1] 



NATURE 



177 



Das Wasser. By Dr. O. Anselmino. Pp. vi + 122. 



(Leipzig : B. G. Teubner.) Price 1.25 marks. 

 This booklet is the 291st volume of a popular scientific 

 and literary series. It embodies the material used in 

 a course of experimental lectures given at Griefswald 

 in 1907. The subjects dealt with include the chemistry 

 of water, mineral waters, the purification of water, 

 drinking water, mineral waters, and diffusion. The 

 text is illustrated by forty-four diagrams, most of 

 which have been taken from text-books of chemistry, 

 to which due acknowledgment is made. The author 

 has brought together a large array of facts, the 

 tabulated analyses of various waters, including a long 

 series of mineral waters, being a conspicuous feature 

 of the book. The chapter of chemistry covered by 

 the title is an important one, and it is probable that 

 its treatment in a separate volume may prove to be a 

 convenience to a considerable class of readers. 



What Nature Is. An Outline of Scientific Naturalistn. 

 By Chas. K. Franklin. Pp. iv + 74. (Boston : 

 Sherman, French and Co., 191 1.) Price $0.75 net. 

 A WELL-WRITTEN argument for " scientific naturalism " 

 as against the argument from design, which sees in- 

 telligence in nature, inferring therefrom a creator. 

 Mr. Franklin rejects anthropomorphic theism, also 

 idealism, but seems to finish up in a kind of mysticism. 

 " It is the character and quality of matter and energy 

 to develop " man and the social process, just as it is 

 for them to manifest themselves in the inorganic and 

 organic processes. New thoughts, feelings, volitions, 

 religion, Sec, are merely manifestations of "radiant 

 tand gravitant energy." But somehow we shall eventu- 

 ally "be able to comprehend what the universe is, 

 conceive infinite time and infinite space by looking in 

 upon ourselves and seeing the infinite repeated in us, 

 and understand the inmost nature of things. Just as 

 the time was when life was not self-conscious, then 

 became self-conscious and class-conscious, and to-dav 

 is imperfectly socially conscious ; and so the time will 

 come when we shall be universally conscious " (pp. 

 71-72). 



Perhaps so; it is interesting as a speculation, and 

 the author has probably been reading Dr. Bucke's 

 ^'Cosmic Consciousness." But Mr. Franklin is rather 

 dogmatic, and is a little apt to slide into speculation 

 suddenly after writing a good deal of sensible science; 

 the reader therefore has to keep an eye on him, and 

 to guard against too hasty following. Moreover, the 

 reduction of evervthing to " energv " does not in the 

 least resolve the ultimate mystery of things, as Tyndall, 

 for instance, saw plainly enough. 



Morale de la Nature. By M. Deshumbert. Second 

 edition. Pp. 96. (Paris: Schleicher Fr6res, 1911.) 

 Price 1.50 francs. 

 We have here the second French edition of a book 

 which, since its first appearance, has been translated 

 into English by M. I. M. Hartmann, and published 

 by Mr. D. Nutt, under the title, "The Ethics of 

 Nature." The original work led to the formation of 

 the " Ethics of Nature Society," which is an asso- 

 ciation for the harmonious development of life. The 

 present edition of M. Deshumbert's book has been 

 revised and enlarged. 



Carnations and Pinks. By T. H. Cook, J. Douglas, 

 and J. F. McLerd. With eight coloured plates. 

 Pp. xi+ii6. (London: T. C. and E. C. Jack, 

 n.d.) Price is. 6d. net. 

 The latest addition to the " Present-Day Gardening " 

 series will be welcomed by all active horticulturists. 

 Being the work of expert cultivators of the flowers 

 with which it deals, the volume should soon become 

 widely known and consulted on account of the prac- 

 tical hints it contains. 



NO. 2162, VOL. 86] 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Stability of Aeroplanes. 



The following simplification of Lanchester's 

 for longitudinal stability 

 useful. 



His formula is 



4/H J tan 7 



formula 



of tailed monoplanes may be 



* = 



\K'*'rCpea/3/ 



( " Aerodonetics " p loi). 



V,;- ioW\ 



Here H„ is the height corresponding to the normal velocity 

 of the machine =V„72^and I=WR"^ where R is the radius of 

 gyration about a transverse axis through the centre of gravity, 

 and K is ^''W/VJ, where W is the mass in pounds. 



c = yo, C— 0"7, p = o-o8 pounds per cubic foot, 6 = about o '6 

 for tails ot moderately high aspect ratio, so that c-Cpe = o'i 

 nearly. 



Hence 



/V^* tan -y 



(See " Problem of Flight," 2nd edition, p. 114.) 



For most machines with pterygoid aerofoils of approved 

 camber 7 and /3 are about ^ radian. 



Further ihevahieofW (pounds not poundals) is connected to the 

 supporting area by approximately the equation W=0'Oor6 AV'-^ 

 so that V = 20 to 30 V(W/A), or say 30 ^/w, where w is the lift 

 in pounds per sq. foot. 



Hence approximately 



/ X 30* xw^x^ 



taking *= l'5 and writing W = wA, we get very nearly 



500V 



w - + 60W 



't) 



thus expressing the length of the tail in terms of the radius 

 of gyration, the loading per sq. foot, and the ratio of the 

 supporting area to the tail area. 



For example, if — -lo, and ro-2 lbs. per sq. foot, 

 a 



1= — 10-35 + 300) or roughly gR*. 

 500V / 



Thus a machine the radius of gyration of which is 7 feet, loading 

 2ll)s. per sq. foot, and having lo per cent. t«il area, needs a 

 tail with ? X 7-, say 30 feet radius of action ((/ IJleriol machine). 



Herbert Chatley. 

 Tang Shan, Chih-Li (via Siberia), February 27. 



The Daintiness of the Rat. 



One of the principal sights in Bordighera is the garden 

 of the Villa " Charles Garnicr." It is called after its late 

 owner, the famous designer of the Grand Opera at Paris 

 and the Casino at Monte Carlo. It was probably when he 

 was engaged in building the Casino that he acquired the 

 large and valuable property which bears his name. 



The garden covers more than five acres, and is a mass 

 of tropical and subtropical vegetation. The banana trees 

 bear fruit which ripens every year. The gardener, a very 

 civil and intelligent man, speaks English, and he told me 

 he had worked for more than a year in Kcw Gardens, 

 which he much admires, and endeavours to imitate when 

 his means permit. He was especially proud of his ticket- 

 ing the plants after the Kew model. 



Not being a botanist, I was unable to appreciate 

 adequately his attention in showing me the treasures of 

 his garden, and it was perhaps owing to his perceiving 



