April 27, 1893] 



NATURE 



619 



pressure were not applied. In one case a cylindrical piece of steel, 

 i" long and f" in diameter, was bored through two-thirds of its 

 length by a hole Vu" in diameter, in which a thermal junction was 

 placed. The mass was heated to looo" C, and it was found that 

 without the application of pressure recalescencQ occurred at 

 650° C, but when a load of 9 tons per square inch was 

 applied, recalescence occurred at 620° C, and was com- 

 paratively feeble. The experiment, it need hardly be said, 

 is one very difficult to make, and could only be done by 

 those having command of special apparatus. Other experi- 

 ments were carried out, the result showing that the recal- 

 escence point is lowered by pressure, but it was found that the 

 lowering was not affected, unless the load was applied at a tem- 

 perature well above that at which recalescence takes place. 

 Experiments were made with Newton's alloy of bismuth, lead, 

 and tin, the full results of which will be published at some future 

 time. In considering the whole scope of the report, the author 

 said that it might be asked what evidence had been gathered as 

 to the mode of action of added elements, and whether it appeared 

 that the atomic volume of the added element had a dominating 

 influence on the mechanical properties of the mass in which it is 

 hidden? The true action of an added element, the author 

 pointed out, may readily be masked by its action as a deoxidiser. 

 Notwithstanding these difficulties, it is undoubtedly proved that 

 bismuth, potassium, and tellurium, all of which have atomic 

 volumes, greatly lower the tenacity of copper. Arsenic, which 

 hasalar><eratomic value (13 -2) than copper (7 'i) confers strength 

 on copper, but it is very certain that the limit of elasticity, and 

 the ductility of a metal are greatly influenced by the presence of 

 an element with large atomic volumes. This fact may be of 

 more molecular significance than the diminution of tenacity, 

 to which, for the sake of simplicity, attention was mainly 

 directed, when the early experiments on gold were made. 



In the discussion which followed the reading of the paper a 

 number of speakers took part. The most important contribu- 

 tion was that of Dr. Watson, of the Broughton Copper Com- 

 pany, who brought forward some practical experience to re- 

 inforce the deductions of the author. Mr. Arnold, of the 

 Technical Schools, Cambridge, read a very long manuscript, 

 which it would be rash on our part to attempt to abstract, and 

 which we cannot afford the space to give in full. Mr. Hadfield, 

 of Sheffield, questioned the accuracy of the beta form of iron 

 theory promulgated by Osmond and adopted by the author. 

 The point is one of considerable importance, but requires a wide 

 field for its discussion. 



On the whole it cannot be doubted that the report is a most 

 valuable contribution to the scientific knowledge at the com- 

 mand of the engineer, and were the attention called to the 

 action of bismuth on copper its sole result, the labours of the 

 committee would not be without warrant. 



The summer meeting of the institution will be held this year 

 at Middlesborough on August I and three following days. 



CONIFERS} 

 'T'HIS is a bulky volume of nearly 600 pages, and contains a 

 vast amount of information. If the Royal Horticultural 

 Society had published nothing but this since 1891 they would 

 have amply satisfied those who are interested in conifers, and 

 have keenly felt the want of such a book of reference as the one 

 now under notice. Some of the papers published in the report 

 could have been omitted without loss, but on the whole the 

 editors have done their work well. In the preface they say, in 

 sending out this memorial of the Conifer Conference, 1891, "we 

 would draw attention to the fact that it contains far more than 

 a mere verbal report of the conference. Dr. Maxwell T. Masters, 

 F.R.S., and Prof. Carl Hansen, of Copenhagen, having promised 

 at the time to recast their notes more fully. This they have 

 done most kindly, and with infinite labour and research, but not 

 without some little expenditure of time, the final sheets of MS. 

 having only come into our hands in July, and the corrections 

 extending up to September 29. 



" The names adopted by Dr. Masters and Prof. Hansen may, 

 of course, be relied upon as representing the latest decisions of 

 botanical science in England and on the continent of Europe 

 respectively, though future research may necessitate some still 

 further slight alterations. However, the hitherto inextricably 

 confused nomenclature of conifers may safely be described as 

 settling down upon the lines adopted in this volume by these 

 ' Report of the Conifer Conference, 1891 (issued November, 1892). 



NO. 1226, VOL. 47] 



two eminent authorities, who, although not yet in absolute 

 agreement, will be found to approach very nearly." 



The list of conifers and texads, by Dr. Masters, is by far 

 the most important contribution to the nomenclature and 

 synonymy of conifers which has appeared since the publication 

 of Parlatore's monograph in De Candolle's"Prodromus"in 1868; 

 it is much more complete than Beissner's " Handbuch der 

 Coniferen-Benennung," and the more recent "Handbuch der 

 Nadelholzkunde," of the same author. There seems no 

 reason to doubt that Dr. Masters's list will be used and followed 

 by English systematists generally. Dr. Masters, in drawing up 

 the list of genera, follows Bentham and Hooker's "Genera 

 Plantarum " as the standard authority. A few deviations from 

 it have, however, been made in accordance with more recently 

 obtained knowledge. Pseudolarix is accorded generic rank 

 (and not united with Larix,as in the " Genera Plantarum," whose 

 authors had not seen male fl >wers) ; Keteleeria too, after a 

 careful study of living material, has been separated from Abies 

 and reinstated as a genus — Dr. Masters's studies having on these 

 points proved the justice and accuracy of Carriere's views. The 

 Chilian Prumnopitys is restored to generic rank, and separated 

 from Podocarpus, with which it was united by Bentham and 

 Hooker. 



The Pinetum Danicum of Prof. Carl Hansen is unsatis- 

 factory, and its omission from the report would have been 

 desirable. It is a somewhat ambitious performance, but in bulk 

 is very largely made up of extracts from books and periodicals. 

 Many of the records are certainly useless ; for instance, under 

 Pitius longifolia, it is stated : "one plant, however, exposed out 

 of doors does not appear to have suffered " ; this Indian species 

 is tropical in its requirements, and as it will not grow out of 

 doors even in the south of England, it is in the highest degree 

 improbable that it would, even under the most favourable con- 

 ditions, exist in the open air in Denmark. A curious mistake 

 occurs on p. 372, where the Viennese botanist, Prof. Giinther 

 Beck, Ritter von Mannagetta, figures as Prof. Giinther, Knight 

 of Beek von Managetta. On p. 330 Prof. Hansen remarks 

 under Prumnopitys that its wood is much valued by " ebon- 

 ists." He probably means cabinetmakers (ebenistes). Tsuga 

 hooka-iana and T. pattoniana are kept up as distinct species by 

 Hansen ; but Prof. C. S. Sargent, who is familiar with the two 

 forms in their native habitats, has no hesitation in regarding 

 them as specifically identical. Hansen accords generic rank to 

 Biota, Thuyopsis, and Chama2cyparis, the first and second being 

 merged into Thuya, and the third into Cupressus by Dr. Masters. 

 It is rather annoying to find the obsolete geographical ex- 

 pression " New Holland " constantly used by Hansen. New 

 Holland and South-east Victoria are given as the native countries 

 of one species. 



The coniferse of Japan, by H. J. Veitch, is a valuable paper. 

 From it we learn the somewhat startling fact that, in proportion 

 to the area of the country, the flora of Japan contains more 

 coniferous species than that of any other country in the world. 

 Japan boasts of forty-one species and thirteen genera, whereas 

 in the whole of Europe there are but eighteen species and seven 

 genera. 



A. D. Webster, "Conifers for Economic Planting." Mr. 

 Webster is a practical forester of wide experience, and he con- 

 siders that out of all the conifers cultivated in Britain only 

 sixteen can be utilised in an economic sense, or for truly profit- 

 able planting. These are the larch, silver fir, Corsican pine, 

 Douglas fir, Pinus Strobus, Scotch fir. Thuya gigatitea, Spruce 

 fir, Austrian pine, Pinus Pinaster, Abies nordmanniana. Sequoia 

 setnpervirens, Cupressus macrocarpa (or, as Mr. Webster calls 

 it, C. lamberliana), Cedrus atlantica, Pinus rigida, and 

 Cupressus la-Msoniana. The order in which these names are given 

 represent the relative value of the trees as timber producers. 

 Under each heading Mr. Webster gives valuable data as to rates 

 of growth under different conditions as regards soil, eleva- 

 tion, &c. 



In a compact paper of thirteen pages Mr. W. Somerville gives 

 a very good restivii- of the present state of our knowledge of 

 the quality of coniferous timber as affected by sylvicultural 

 treatment. Mr. Somerville's remarks are sure to be perused 

 with profit by landowners and foresters. 



Mr. D. F. Mackenzie, on the timber of exotic conifers : 

 uses and comparative value, contributes much valuable in- 

 formation. Taking the value of Scotch fir timber at lOO, the 

 author calculates that of Cupressus macrocarpa at 190 and that 

 of C. lamberliana at 283 ; as these two names represent one and 



