December 1, 1894.] 



KNOWLEDGE 



279 



The filtration of water, on a large as well as on a small 

 scale, has acquired quite a different significance since the 

 bacteriology of water has sprung into existence. (Surgeon- 

 Major Johnston's short treatise on " the relative efficiency 

 of certain filters for removing micro-organisms from water.") 

 He has examined the Atkins' patent water filter, Maignen's 

 table " filtre rapide," and the Nordmeyer-Berkefeld filter, 

 and the Pasteur-Chamberland filter. The first two he 

 considers useless for sterilizing water. The Pasteur- 

 Chamberland filter is, in his opinion, the best and only one 

 on which reliance can be placed for permanently sterilizing 

 water. The investigations were carried on in the Public 

 Health Laboratory of Edinburgh University. 



" From the Greeks to Darwin ; an outline of the 

 Development of the Evolution Idea," is the title of an 

 instructive work by the well-known palseontologist, Prof. 

 H. F. Osborn, of the Columbia University, New York. 

 Evolution, as a natural explanation of the origin of the 

 higher forms of life, may have succeeded the old mythology 

 in Greece, and (ippmrs to have first developed from the 

 teachings of Thales and Anaximander (b.c. 611-547) with 

 those of Aristotle. This great philosopher had a general 

 conception of the origin of higher species by descent from 

 lower species, and he even stated the theory of the survival 

 of the fittest, though rejecting it as an explanation of the 

 evolution of adaptative structures. He also believed that 

 there was no fortuity in evolution, but that the succession 

 of forms of life was due to the action of an internal per- 

 fecting principle originally implanted by the Divine 

 Intelligence. What is this idea but the modern " law of 

 progress," so strongly proved by the discoveries of paleon- 

 tology '? We would, however, humbly suggest that in 

 these matters, as in others, the Greeks took their teaching 

 from Egypt, where the problems of life and of creation had 

 been deeply pondered over and partly explained to initiates 

 of their sacred mysteries. 



We have received a specimen from Messrs. Newton & Co. 

 of their " spectrum top," which consists of a disc, half of 

 which is white and half black. Over the white half are 

 four groups of concentric lines. Upon being spun the 

 black disappears, and the whole face is covered by four sets 

 of circles, each of which assumes to the eye a peculiar 

 tint. The hues appear to be dark from the centre when 

 the top is spun from the right, and lighter when spun 

 from the left. 



Natural Science for the last two months gives some very 

 interesting facts with regard to the way in which animals 

 can gradually adapt themselves to new conditions, even 

 when those conditions are at first fatal. From an account 

 in the Pittshurij Diapatch, it appears that in the cold-storage 

 warehouses in Pittsburg tliere were originally no rats nor 

 mice. The temperature in the cold rooms was too low. 

 But after a few months rats were at work in the rooms 

 where the temperature was constantly kept below the 

 freezing point, and they were clothed in long and thick 

 fur. Cats were, therefore, turned loose in the cold rooms, 

 but they pined and died. At last a cat with unusually 

 thick fur was found which thrived there, and by careful 

 imrsing, a brood of seven kittens was developed. They 

 have been distributed among other cold-storage houses of 

 Pittsburg, and have created a peculiar breed of cats adapted 

 to the conditions. The cats are now so acclimatized that 

 they cannot live in the open air during the hot season. 



Koticts of JSoofts. 



JJi/ Order of the Sun to Cldle, to see Ins Total Eclipse, 

 April 16th, 189S. By J. J. Aubertin. Pp. 1.52. (London: 

 Kegan Paul, Trench, Triibner and Co., 1894.) To the 

 casual reader of astronomical literature who desires to 

 know how an eclipse expedition appears to a layman's 

 mind, we commend Mr. Aubertin's narrative. The author 

 is an enthusiastic observer of the progress of astronomy, 

 and, though in the evening of life, he journeyed to Chile in 

 April, 1898, in order to witness the most impressive of 

 celestial phenomena — a total eclipse of the sun. And just 

 as an onlooker sees more of a fight than any of the 

 combatants, so an intelligent spectator can take in the 

 iistonishing beauty of a solar eclipse better than the 

 astronomer whose whole being, during totality, is wrapt 

 up in the photographic camera or spectroscope of which 

 he has charge. Mr. Aubertin was fortunate in selecting 

 Chile as his destination, for he was not only able to observe 

 the eclipse in all its fulness, but could also watch the 

 proceedings of Prof. Schaeberle's party. His book contains 

 a fine photograph of the professor, and four other plates- 

 one representing a symmetrical corona of the familiar 

 "Catharine wheel" type. After the eclipse had taken 

 place, Mr. Aubertin made a pilgrimage to Arei^uipa, La 

 Paz, and Cuzco, then to Lima and Ban Francisco, and 

 then he crossed the line (for the sixteenth time) and 

 returned home. The incidents of his journeys on sea and 

 land are described with a certain amount of pleasantness, 

 but we think the book wUI only be appreciated by a limited 

 circle of readers. It will be more interesting to the author 

 than to anyone else. 



Forest Birds : their Haunts and Habits. By Harry F. 

 Witherby. Pp.98. (London: Kegan Paul, Trench, Triibner 

 & Co., 1894.) Mr. H. F. Witherby's papers on popular 

 natural history are well known to our readers. In the 

 dainty little volume under review, some of these papers 

 are printed with others contributed by the author to Science 

 (Jossip : the whole collection forming an interesting account 

 of the haunts and habits of eight species of forest birds. 

 The chapters of the book are not, however, merely reprints 

 of articles, but rather the original papers rewritten for 

 publication in book form. Mr. Witherby writes easily, 

 clearly, and with the accuracy that comes from personal 

 observation of the birds he describes. His book is embel- 

 lished with thirty illustrations, most of them full-page 

 plates, for which we have nothing but praise. They are 

 among the finest specimens of process blocks that we have 

 yet seen, and the paper upon which they are printed brings 

 them out perfectly. The book is attractive as well as 

 instructive, and is just the sort of volume to present to 

 young beginners of the study of Nature, while children of 

 an older growth will derive profit from its perusal. 



Practical Methods in Micrvscopi/. By Charles H. Clark, 

 A.M. Pp. 210. (Boston : 1). C. Heath it Co. London : 

 Isbister & Co., 1894.) This is a practical handbook to the 

 microscope, and, as a book containing descriptions of the 

 many processes connected with microscopical researches, 

 couched in simple language, and suitable for beginners 

 and private workers, we heartily welcome it. The methods 

 described are workable, and they refer to many branches of 

 scientific study. The preparation and observation of sections 

 of plants, animal tissues, and rocks are fully treated, as well 

 as the preparation and examination of crystals and bacteria. 

 There is also a chapter on photo-micrography. The theo- 

 retical principles involved in the construction of the micro- 

 scope are briefly and accurately explained, and also the 

 principal phenomena of polarized light, so far as they have 



