564 



NATURE 



[April 13, 1893 



The French Minister of War has recently had some experi- 

 ments made on the resistance of ice. With a thickness of 4 

 centimetres (say i-6 inches), it begins to bear the weight of a 

 man marching alone ; at 9 centimetres detachments of infantry 

 in files may go on it ; at 12 centimetres it will carry " pieces de 

 8 " on carriages, and so on ; till at 29 centimetres, it will bear 

 the heaviest weights. M. Forel {Rev. Set.) sees danger in this 

 note ; if an officer, trusting in the figures, ordered a troop on 

 ice of measured thickness, he might, in some cases, be courting 

 catastrophe. Those estimates, in fact, apply only to young ice, 

 lamellar ice in process of freezing. When ice has for a few 

 weeks been subject to alternations of temperature it changes in 

 structure and loses much of its tenacity. The old ice of a pond, 

 absolutely compact in appearance, is traversed by a multitude 

 of vertical fissures dividing it into irregular prismatic needles, 

 comparable in arrangement to columns of basalt, and from a 

 half-centimetre to i or 2 centimetre-; in thickness. The struc- 

 ture becomes evident on breaking su Idenly, in sunlight, a block 

 of ice taken from a pond. Under these conditions old ice has 

 not nearly such resistance as young ice. 



The Michigan Mining School has published a " Catalogue," 

 in which a full account is given of the various departments of its 

 work. The institution was established and is supported by the 

 State of Michigan "in accordance with that liberal educational 

 policy which has placed the university of Michigan amongst the 

 foremost educational institutions of America." It is stated with 

 admirable directness that students at the school are supposed 

 •'to understand what they are there for, to attend strictly to 

 that business, and to conduct themselves as gentlemen." 



The new number of the Internationales Archiv fiir Ethno- 

 ^/-a/-^/(? (Band vi , Heft i.) is occupied wholly with the con- 

 cluding part of Dr. W. Svoboda's interesting notes (in German) 

 on the inhabitants of the Nicobar Islands. The illustrations, as 

 usual, are excellent. 



The American Philosophical Society, Philadelphia, has 

 issued a new instalment of its Proceedings (vol. xxx., no. 139). 

 It opens with a paper on the mutual relations between the orbits 

 of certain asteroids, by Daniel Kirkwood. There are also 

 articles by Dr. D. G. Brinton on the Betoya dialects, and on 

 the Etrusco- Libyan elements in the song of the Arval brethren ; 

 and by Prof. E. D. Cope on the phylogeny of the vertebrata 

 (with two cuts), on some points in the kinetogenesis of the limbs 

 of vertebrates, and on false elbow joints (with two plates). 



A " Catalogue of Australian Mammals, with Introductory 

 Notes on General Mammalogy," by J. D. Ogilby, has been 

 published by order of the trustees of the Australian Museum, 

 Sydney. Mr. E. P. Ramsay states in the preface that the work 

 contains descriptions of all known mammals indigenous to Aus- 

 tralia, with notes on allied fossil forms, compiled from various 

 sources which are duly acknowledged by the author. Nearly 

 all the species, Mr. Ramsay says, are represented by one or 

 more specimens in the Museum. 



The new number of Records of the Australian Museum 

 (vol. ii. no. 4) contains the following papers : — On further 

 traces of Meiolania in N. S. Wales, by R. Elheridge, jun. ; 

 notes on Australian Aquatic Hemiptera (No. i) by Frederick 

 A. A. Skuse ; remarks on a new Gyria from New South Wales, 

 by Frederick A. A. Skuse ; geological and ethnological observa- 

 tions made in the valley of the Wolloudilly River, at its 

 junction with the Nattai River, Counties Camden and West- 

 moreland, by R. Etheridge, jun, 



A VOLUME on " Ironwork from the Earliest Times to the 

 End of the Mediaeval Period," by J. Starkie Gardner, has been 

 issued as one of the South Kensington Museum art handbooks. 

 NO. 1224, VOL. 47] 



It is mainly artistic, but the author has a good deal to say that 

 is of scientific interest, and his scientific training enables him 

 to present in an orderly way the historical facts with which he 

 is chiefly occupied. Ironwork of later times will be dealt with 

 in a second volume. 



Some time ago Mr. C. E. de Ranee prepared for the infor- 

 mation of the County Councils a very useful map of the river 

 basins in England and Wales, the object being to define the 

 natural jurisdiction of joint committees of county councils for 

 the prevention of pollution of rivers under section 14 (iii.) of 

 the Local Government Act, 1888, and other matters requiring 

 united control. The map has now been reprinted by J. E. 

 Cornish, Manchester. 



The Geological Survey of Canada is issuing a valuable series 

 of "Contributions to Canadian Palaeontology." The fourth 

 part of the first volume, by J. F. Whiteaves, has just been pub- 

 lished. It deals with 'the fossils of the Devonian rocks of the 

 islands, shores, and immediate vicinity of Lakes Manitoba and 

 Winnipegosis, and is well illustrated. 



The York School Natural History, Literary, and Polytechnic 

 Society has issued its fifty-ninth annual report. Much genuine 

 interest in science is evidently maintained among the members 

 of this society by the part they take in its work. The Natural 

 History Club held in the course of the year twenty-three meet- 

 ings, sixteen of which were occupied with the club's regular 

 business of reporting and commenting on finds and observations. 

 The first part of an elaborate " Topographische Anatomie des 

 Pferdes," by W. Ellenberger and H. Baum, has just been issued, 

 the publisher being Paul Parey, Berlin. 



A NEViT sclerometer, constructed by M. Paul Jannetaz, was 

 recently presented to the French Academy of Sciences. Like 

 that invented by Seebeck, it measures the hardness of 

 bodies defined as their resistance to scratching. It consists 

 essentially of a platform rendered horizontal by means of level- 

 ing screws, and furnished with various motions which enable 

 the observer to place any part of the body whose hardness is to 

 be determined underneath a vertical point. This point is carried 

 by an arm of a balance, which can be adjusted by a coarse and 

 a fine movement, so as to bring the point and the body into 

 contact without a shock. The beam is provided with pans 

 carrying the weights which produce the pressure. At one 

 extremity the beam carries a screw for horizontal adjustment, 

 at the other a hollow bar to hold one of a set of points, such 

 as copper or steel points of various angles, straight or curved, 

 forming certain definite angles with the platform when mounted, 

 or crystalline points clamped in metallic jaws. A very light 

 aluminium beam is used for bodies which are only tested with 

 light weights. As a rule the points trace a small circle on the 

 body, which, when examined under the microscope, indicates 

 the hardness of the substance in various directions. Homo- 

 geneous bodies like metals need only be moved in one direction. 

 The scratch is viewed by reflection, greater softness being in- 

 dicated by greater breadth. An interesting fact concerning the 

 relative hardness of copper and zinc has been brought to light 

 by means of this apparatus. Most authors regard zinc as harder 

 than copper. If, however, the metals are examined in a 

 sufficiently pure state, it appears that copper is the harder of the 

 two. This removes an exception to the rule that the harder the 

 body the less its atomic volume. 



In a paper communicated to the Royal Prussian Academy 

 of Sciences (see also Electrician, vol. xxx. p. 660) Dr. 

 Philipp Lenard gives an account of some interesting ex^ 

 periments on the rays given out by the kathode of 

 a Geissler tube which produce phosphorescence. Thin metal 

 plates being to a great extent transparent to these rays by 



