108 



KNOWLEDGE 



[June 1, 1898. 



through the pipes into receivers, whence it falls by gravity 

 into weighing machines, and then, again by gravity, into 

 the craft sent out by the purchasers to carry it away. 



Natural Science announces that the work of remounting 

 the great series of microscopic preiJarations made by the 

 late Prof, de Bary, and acquired by the British Museum, 

 is nearly completed. To students of botany the presence 

 of this large collection in the country will be a great 

 benefit. 



In the last issue of the " Proceedings of the Zoological 

 Society," Mr. E. Lydekker describes an interesting series 

 of Cetacean remains from the eocene of the Caucasus. 

 Among these, special importance attaches to certain bones 

 belonging to the imperfectly-known creature designated 

 ZeiKjlodon, wliich Prof. D'Arcy Thompson has recently 

 endeavoured to remove from its assigned position among 

 the whales to associate it with the seals. The most 

 important specimen among the new find is a humerus 

 bone of which but one example has been hitherto known, 

 and the study of this leads the author to conclude that 

 Zew/lodon is much more likely to be an ancestral Cetacean 

 than a seal. 



An important find of water is reported within "the 

 London Basin " of geologists, in Windsor Forest. After 

 boring for 1234 feet, water was found, and rose seven feet 

 above the surface, though the site is on a hill 223 feet 

 above sea level. This welcome supply comes from the 

 lower greensand. As a Commission is now at work on 

 the London Water Supply question, this discovery may 

 have important results. 



The Board of Agriculture has issued a valuable report on 

 rust or mildew on wheat plants. It contains a complete 

 account of the life-history of the fungus of ordinary 

 mildew, Puccina f/raiiiinis, as well as that of spring-rust 

 and mildew, PiK-cimi ruhijo vera, with a discussion of 

 the conditions favourable for their propagation, and the 

 best means of averting them. It is illustrated by some 

 exceUent colloured plates by Mr. Worthington Smith. 



^-•-^ 



Dr. J. Rahon has recently contributed to the Anthropo- 

 logical Society of Paris an interesting paptr entitled 

 Piecherches sur lea Osaenients Humnins Ancien et Preliistoriijices. 

 This paper is the fruit of most laborious investigation. 

 The author concludes that the bones both of men and 

 women were rather heavier and more powerful in ancient 

 times ; also that the tribes of neolithic times in Western 

 Evrope were of a medium height, of about 1-G3 metres. 



1 ♦ I 



The Rev. F. J. Smith, Millard lecturer in mechanics 

 at Trinity College, Oxford, has devised a means by which 

 pictures of old coins, and similar objects, can be made 

 electrically. The coin, medal, or engraved plate of which 

 a figure is required, is made to form one of the metallic 

 coatings of an electrical condenser ; a photographic plate, 

 or a piece of bromide paper, being placed between the two. 

 When a condenser so arranged is subjected to rapid charge 

 and discharge, by connecting the coatings with the terminals 

 of an induction coU, or a similar source of electricity, for 

 a fraction of a second, the prepared surface of the dry 

 plate is chemically altered, and upon developing the plate 

 in the usual manner a picture of the coin or medal will 

 be found upon it. Pictures can be produced in this 

 manner even when the sensitized plates have been exposed 

 to full daylight. The best results are obtained by con- 

 ducting the process in oxygen gas under a pressure of 

 about two atmospheres. 



It has been resolved by the Council of the Zoological 



Society to award the Society's Silver Medal to Donald 



Cameron, of Lochiel, and .John Peter Grant, of Rothie- 



murchus (luverness-shire), in recognition of the eflbrts 



they have made to protect the osprey {Pandiim Iniliatiis) 



in Scotland. The osprey, formerly common in many parts 



of the British Isles, has become so rare of late years that 



it is stated that only three pairs of this bird have been 



known to breed in this country for some years past. 

 — i • I — 



Those who desire to keep in touch with the progress of 

 science outside their own departments will welcome the 

 appearance of the second volume of the " Year Book of 

 Science" (Cassell & Co.), edited by Prof. T. G. Bonney, 

 F.R.S. It has been extended so as to include geography 

 and anthropology, and more space is devoted to anthro- 

 pology. The list of contributors contains many well-known 

 names. There is an index of subjects as well as one of 

 authors. 



M. Rykatchefhas made an investigation of the variations 

 in the temperature of the air over the oceans in the tropics, 

 which is described in the Transactions of the St. Petersburg 

 Academy of Sciences for October 19th. He finds that 

 the minimum daily temperature is reached about one and 

 a half hours before sunrise, and the maximum almost 

 immediately after mid-day. The variation of the mean 

 temperature throughout the whole twenty-four hours is 



very small, being only 2-9° Fahrenheit. 

 — ^-*~-i — 

 M. Angot exhibited several beautiful photographs of 

 cirrous clouds at the French Physical Society on Feb- 

 ruary Hrd. In order to stop out the blue colour of the sky, 

 coloured screens were employed, the best results being 

 obtained by using a solution of copper sulphate (ten parts) 

 and potassium bichromate (one part), to which a few drops 

 of sulphuric acid is added. With such a solution in front of 

 the lens of a camera, and orthochromatic plates, excellent 



cloud photographs are obtainable. 

 — ►-♦-* — 

 The mammoth gum trees of Australia are the largest 

 trees in the world, not excepting even the sequoias of 

 California. The loftiest tree on the globe, according to 

 Baron von Miiller, is the Eucahjptus reynans. One of 

 these trees in the Cape Otway ranges measured, when 

 felled, 415 feet in length. Gum trees grow very rapidly. 

 The FAicah/ptus i/loliidas grew 40 feet high in four years in 

 Florida, with a stem a foot in diameter. Trees of the 

 same species in Guatemala grew 120 feet in twelve years, 

 and had a stem diameter of nine feet. 



A few facts significant of progress in India are noted 

 by Dr. H. R. Mill in a recent number of Nature. He says 

 that the newly-published report of the Bengal census 

 shows that there is a steady transference of population 

 from the most densely to the more thinly-peopled parts of 

 the province. Would that the same remark could be 

 made as to the population of England ! Mohammedanism 

 is increasing rapidly in Bengal, and the custom of widow 

 marriage among Hindoos has become common. 



From measurements of an arc along the parallel of 47s° 

 in Russia, M. Venukoff has found a length of 1,446,402 

 metres for a difference of longitude of 19° 11' 5.'j-11", or 

 75,336 metres (46^ miles) per degree. The rate of 

 diminution in the lengths of degrees of longitude deduced 

 from the Russian results does not agree with that given by 

 French and English measures ; it indicates a polar com- 

 pression of — ^ — , whereas the value given by Clarke 

 is — 1 — . 



