February 23, 1893] 



■NA TURE 



397 



reported in the new instalment of the Transactions of the Insti- 

 tution of Engineers and Shipbuilders in Scotland. Mr. Carey, 

 in the course of his reply to the various speakers, alluded to the 

 question as to the value of annealing steel. He said that, so 

 far as his experience went, annealing steel certainly removed all 

 stress. At the Forth Bridge they were very curious about this 

 subject. They had a single strip of steel, which they strained 

 up to some 30 times, to about 25 tons on the square inch. After 

 every straining, it was annealed. That went on for days and 

 weeks, and the steel seemed to be literally the same as when 

 they started. The experiment grew wearisome, and ultimately, 

 when the strain was run up inadvertently to about 30 tons per 

 square inch, and the specimen finally broke, it was almost a 

 relief, but it proved that the annealing of steel removed all 

 strain, and that, although injured, if annealed, it seemed to 

 recover its former properties. 



A VALUABLE synonymic and bibliographical catalogue of the 

 New Zealand land and freshwater Mollusca, by H. Suter, was 

 communicated to the Linnean Society of New South Wales at 

 its meeting on December 28. In 1880 Prof. Hutton, in his 

 " Manual of the New Zealand Mollusca," enumerated 125 

 species of land, fresh, and brackish water molluscs. Since then 

 zoology has made such rapid strides that this fauna is raised in 

 Mr. Suter's catalogue to a total of 178 species, divided by him 

 into 45 genera. The land mollusca embrace 142 species, of 

 which 15 are operculate ; the fluviatile shells are reckoned at 

 32, 12 being bivalves and 7 operculate univalves. This large 

 addition of one-third to the list of twelve years ago is not the 

 greatest advantage the present catalogue has over its prede- 

 cessor ; numerous species are now removed which, by the negli- 

 gence of collectors or»the errors of European authors, were 

 formerly included among the shells of New Zealand. The 

 attention bestowed during the last decade upon the anatomy of 

 the New Zealand snails has furnished data for a more natural 

 classification, while the increase of colonial libraries has facili- 

 tated the quotation of fuller references than were previously 

 available. 



Mr, J, M. Stahl, Illinois, has much to say in the American 

 Agriculturist about the virtues of wood ashes. S peaking of 

 them as a medicine for farm animals, he says he has found them 

 of great value. He has raised swine rather extensively for more 

 than twenty years without cholera or swine plague, and has not 

 lost one per cent, of his hogs from disease. He keeps wood 

 ashes, and charcoal mixed with salt, constantly before his swine 

 in a large covered box with holes two-by-six inches near the 

 bottom. The hogs will work the mixture out through these holes 

 as fast as they want it. He selects ashes rich in charcoal, and 

 mixes three parts of ashes to one of salt. There is no danger of 

 the swine eating too much of this mixture, or of pure salt, if it is 

 kept constantly before them, and they are provided with water. 

 The beneficial effects of the mixture are quite marked, especially 

 when the hogs are fattened on fresh maize. A little wood 

 ashes, given to horses, is also, he maintains, very beneficial. In 

 thirty-seven years' experience upon the farm he has lost but one 

 horse, and this was overheated in the horse-power of a thresh- 

 ing-machine during his absence, and the only "condition 

 powder " he has ever used has been clean wood ashes. The 

 ashes may be given by putting an even teaspoonful on the oats 

 twice a week, but he prefers to keep the ashes and salt mixture 

 constantly before the horses, and has made for it a little com- 

 partment in one corner of the feed box. His experience is that 

 the best condition powder is a mixture of three parts wood ashes 

 to one of salt ; and that when it is given regularly, and reason- 

 able care and intelligence are used in handling the horse, no 

 other medicines are necessary. Mr. Stahl has also great faith 

 in the efficacy of wood ashes as a fertiliser. 

 NO. 1217, VOL. 4.7] 



A valuable paper on the industrial resources of the 

 Caucasus, by an Austrian official, Herr G. Sedlaczek, is sum- 

 marised in the Board of Trade Journal for February. Dealing 

 with the silk industry, the author says that the Russian Govern- 

 ment has spent more money for the furtherance of this depart- 

 ment of trade than for any other industrial purpose in Caucasia, 

 and that the results are in no way commensurate with the 

 trouble and outlay. Although the country possesses innumer- 

 able mulberry trees, in some parts forming veritable forests, 

 and excellently suited for feeding silkworms, although the 

 climatic conditions are favourable, and the inhabitants have from 

 time immemorial been familiar with the working up of the raw 

 material, the most untiring efforts of the Government have 

 proved little else than a struggle to preserve the mere existence 

 of the silk culture and industry. The estimated production of 

 silk in Transcaucasia at the present day is 36,000 pouds, 

 although in 1855 it was 30,000 pouds. The average value of 

 the produce is said to be about 6,000,000 roubles. Consider- 

 able advance has been made in reeling, spinning, and twisting ; 

 new foreign machinery is everywhere at work, and all that is 

 wanting is a good raw material, the production of which is, 

 however, being constantly prevented, on the one hand by dis- 

 ease in the worms, and on the other by the indolence of the 

 producers. The Russian demand for silk is far from covered by 

 native production, silk being annually imported to the value of 

 about 12^ millions of roubles, while the exports amount only to 

 about 3,000,000 roubles in value. In spite of protective duties 

 the imports are increasing while the exports are decreasing. 



Many marine animals (radiolaria, ctenophora, &c.) rise and 

 sink slowly in the water, having some means, apparently, of 

 changing their specific gravity. This has been recently studied 

 by Herr WQTWorvi{PflilgersArchiv), in the case of ThalassicoUa 

 nucleaCa, a radiolarian about the size of a pea. It has a central 

 capsule with nucleus, a coarse endoplasm, a vacuole-layer, a 

 gelatinous-layer, and ray-like processes. As a rule, these 

 animals float at the surface. They sink on seizing food heavier 

 than themselves, also when strongly stimulated by shaking, or 

 by chemical agents. It was found that the central capsule and 

 the gelatinous layer are both heavier than sea- water, while the 

 vacuole-layer is lighter. On being stimulated, the pseudopodia 

 (or processes) were drawn into the vacuole-layer, and the pro- 

 toplasm also retired from this, the walls of the vacuoles flatten- 

 ing from without inwards, till at length very little of them was 

 left. Then the animal began to sink. At the bottom the 

 vacuoles were soon regenerated, and the animal rose again. 

 Thus it appears that the vacuole-layer is the hydrostatic appar- 

 atus of these organisms, the vacuole liquid being that part of 

 the cell which is lighter than sea- water, and keeps the cell at 

 the surface. The same probably holds good with other pelagic 

 animals. That the vacuole-liquid is lighter than the sea-water 

 from which it comes is no difficulty, since it is known that 

 living protoplasm is impermeable for many salts. 



A VOLUMETRIC method for determining the amount of 

 chromium in a specimen of steel has become a great metallur- 

 gical desideratum since the good qualities conferred upon steel 

 by its addition have become generally known. Such a method 

 is described by G. Giorgis, of the University of Rome, in the 

 Aiti of the Acccuieinia dei Lined. It is founded upon the 

 formation of potassium chromate and hydrated manganese 

 sesquioxide on adding a solution of potassium permanganate to 

 a solution of sesquioxide of chromium in potassium hydrate. 

 Ten grammes of the steel are dissolved in a mixture of sulphuric 

 and nitric acids (3 to l), the solution is made up to I litre with 

 distilled water, and 250 c.c. are made just alkaline with sodium 

 hydrate, and treated with hot permanganate of potash till the 

 solution assumes a red colour. After cooling the whole is 



