]Mav 27, 1909J 



NA TURE 



3^5 



. iicmical composition of iron on its susceptibility to attack 

 by dilute sulphuric acid ; the influence of the nature of 

 ine sulphuric acid employed on the solubility of iron. 

 The regularity and trustworthy character of the results 

 obtained prove the great utility of this method of deducing 

 the nature of the previous treatment of the metal under 

 examination. 



A paper on the chemical physics involved in the 

 decarburisation of iron-carbon alloys was read by Mr. 

 W. H. Hatfield, of Sheflield. In this the author refutes 

 the view of Dr. WiJst that it is necessary that the temper- 

 carbon be precipitated before elimination. There generally 

 remained at least i per cent, temper-carbon in so-called 

 dccarburised malleable cast iron. 



, The proceedings on .May 14 opened with the presentation 

 of the Bessemer gold medal to .Mr. A. Pourcel, who first 

 manufactured ferro-manganese and silico-spiegel in the blast 

 furnace. A paper was then taken on the electric furnace 

 and the electrical process of steel-making, by W. Roden- 

 hauser, of Saarbriicken. Such furnaces can be divided into 

 two groups, electric arc furnaces and those in which the 

 arc is avoided. The paper contains working drawings 

 and photographs of many furnaces of these types, and 

 notes of their working and defects. 



A paper on fuel from peat was read by Dr. M. Eken- 

 berg, of London, dealing with the author's researches for 

 finding a suitable process for converting peat into fuel 

 without air-drying. .An experimental apparatus for wet- 

 carbonising pcat-pulp and a peat briquette factory are 

 described and illustrated. 



A heat-treatment study of Bessemer steels was con- 

 tributed by Prof. M'William and Mr. E. J. Barnes, of 

 Sheffield University. This paper gives a large number of 

 tests carried out by the authors on commercial English 

 steels of varying carbon content. Many tables of results 

 are appended. 



The Bristol recording pyrometer was described by 

 Messrs. P. Longm.uir and T. Swinden, of Sheffield, 

 together with notes of tests made with this low-resistance 

 " shop-tool " at the works of the Sheepbridge Coal and 

 Iron Company. Mr. C. E. Stromeyer, of Manchester, 

 added another paper to his previous work on the ageing 

 of mild steel and the influence of nitrogen. The net 

 result oT the experiments may be summarised as follows : — 

 (a) the usual tensile and bending tests do not detect those 

 treacherous steels which, after behaving well under the 

 steel-works' tests, fail in the workshop ; (6) the test strips 

 which have been injured on their edges by chisel nicks 

 and then bent clearly indicate that mild steel does change 

 some of its qualities with time, and these changes can 

 be accelerated by heating the samples to the temperature 

 of boiling water. 



Papers were contributed on high-tension steels, by Mr. 

 P. Longmuir ; on tests for hardness, by Prof. Turner, of 

 Birmingham ; and on the determination of carbon and 

 phosphorus in steel, by Mr. A. k. Blair, of Philadelphia, 

 U.S. .A. Papers from the Carnegie research scholars dealt 

 with the special steels in theory and practice, the strength 

 of nickel-steel riveted joints, the preparation of carbon- 

 free ferro-manganese, steels suitable for gears, and gases 

 occluded in steel. 



SCIENTIFIC WORK IN THE ENGLISH 

 POTTERIES^ 



T' 



■"HE English Ceramic Society, founded in 1900, has 

 just issued the seventh volume of its annual Trans- 

 actions. The membership report shows a steady growth 

 from thirty members in the first two years to a little more 

 than 200 during 1907 and 1008. Ten meetings were held 

 during the session 1907-8, at Tunstall, Longton, Hanley, 

 and Fenton. For the current session the president is Mr. 

 F. H. Wedgwood, and the secretary Dr. J. W. Mellor. 



Special attention appears to have been directed to the 

 question of gas-firing, which formed the subject of a paper 

 read by Dr. Seligman in December, 1907 ; of a second 

 paper, by Mr. Schmatolle, read in January, 1908 ; and of 



1 Tr.insaction5 of the English Ceramic Society, vol. vii., Session 1907-8. 

 Pp. xii + 170. (Published by the Society, County Pottery Laboratory. 

 Stoke-on-Trent, Staffordshire.) Price, Non-members, 21s.; Members, loi. 61/. 



NO. 2065, VOL. So] 



a discussion in March, 190S ; as the former speaker dealt 

 with Continental types of furnace, and the latter came 

 over from Berlin, it is evident that those who control 

 the English potteries have something to learn from their 

 Continental colleagues. The advantages claimed for gas- 

 firing are economy of fuel (especially when a battery of 

 kilns is arranged to work in series, using the same gas- 

 current to cool one furnace and heat the ne.\t), a great 

 reduction in breakages and in wear and tear, and, finally, 

 the complete abolition of the smoke nuisance, which has 

 made the " Potteries " and the " Black Country " 

 synonymous terms. 



An important paper is contributed by Messrs. Moore 

 and Mellor on the adsorption and dissolution of gases by 

 silicates, a question that derives great commercial import- 

 ance from tlie tendency which some glazes show to " spit- 

 out " by the liberation of bubbles of gas; the conclusion 

 is drawn that, although the glaze itself may sometimes 

 be responsible for the spitting, the trouble is usually due 

 to the presence of moisture or of organic matter in the 

 " body," and that the nature of the glaze is usually of 

 secondary importance. The uninitiated may well wonder 

 at the nature of the topics referred to in the discussions 

 on " blungers " and on "pugging," but the address on 

 " Porcelain," by the retiring president, at least is free 

 from this obscurity of nomenclature. 



In addition to arranging for scientific meetings, the 

 society has appointed a committee for the purpose of 

 adopting, in conjunction with worlcers in other countries, 

 a standard method of clay analysis. The volume under 

 review affords the fullest confirmation of the statement of 

 the incoming president that, whilst " the society can easily 

 make a president, it is the secretary who makes the 

 society," his contribution including a share in the author- 

 ship of si.\ of the seventeen papers now published. 



THE CULTIVATION OF TEA.'' 

 "T^HIS little pamphlet of sixty-eight pages deals with 

 the cultivation, and particularly with fhe manuring, 

 of tea. A considerable amount of information on the 

 subject has been gained through the experiments of 

 Dr. Mann and others, and has been drawn on freely by 

 the author. Tea requires a heavy rainfall — 100 inches is 

 mentioned as a suitable amount — and rather special con- 

 ditions of cultivation obtain in consequence. Many of the 

 plantations are situated on very sloping ground, and the 

 soil is liable to be washed away ; the difficulty is met by 

 several devices, among others by growing plants with big 

 leaves alternately with the tea plants, and thus covering 

 the ground so far as possible. Leguminous plants like 

 crotalaria, ground-nuts, dadaps, &c., are commonly used, 

 and when they die or are cut down they supply both 

 nitrogen and organic matter to the soil. Other nitrogenous 

 manures are, however, in use, including oil cake (rape or 

 castor), which is one of the cheapest, and ammonium 

 sulphate. Potash manuring has been found to be very 

 effective, and also phosphates, but lime is not popular 

 among tea-growers. 



The question of quality is dealt with at some length. 

 As a rule, the higher the position of the plantation the 

 better the quality of the tea, but the yield per acre is less ; 

 probably the lower temperature of the high ground is the 

 determining factor. Heavy dressings of manure are pre- 

 iudiclal to quality, but Dr. Mann's experiments are quoted 

 to show that light dressings frequently applied will increase 

 the crop without injuring its quality. 



The results of the manurial trials on the Pitakande 

 Estate, Ceylon, are discussed in detail, and a very useful 

 Pttle chanter is given on the way to conduct such trials. 

 " It is of paramount importance," says the author, " that 

 every owner of a tea plantation should be in a position 

 to experiment for himself and ascertain the most profitable 

 way to manure his crops." This is a very sound position 

 to take. The manures found most profitable at Pitakande 

 would not necessarily be most profitable elsewhere ; the 

 real lesson for the ton-planter is to make his own experi- 

 ments, and so to discover the fertiliser or mixture of 

 fertilisers giving the best results on his own plantations. 



1 "The Fe'tilisation of Tea." By George A. :Cowie. (Tropical ift 

 Publishing OfKce.) 



