358 



NATURE 



[February 8, i9CX3 



exception of AuAlj the compounds are white in colour. The 

 bodies Au.^Al and AuAl, are indicated by well-marked summits 

 in the curve, their freezing points being 625° C. and 1062° C. re- 

 spectively, the latter identical with the freezing point of gold. 

 The lowest melting point is that of an alloy containing only 3 6 

 per cent, by weight of aluminium ; this alloy melts at 527° C. 



The photomicrographs accompanying the paper show that the 

 minute structure of the alloys repeats itself at corresponding 

 points of each branch of the curve. For example, near the 

 summit of the branch corresponding to the pure alloy, AugAl, 

 the photograph shows us more or less hexagonal polygons of 

 this substance almost entirely filling the field, and only separated 

 from eath other by very fine lines of impurity. If we take a 

 section of an alloy a little way below the summit, we see the 

 polygons of Au.^Al surrounded by a ribbon-like network of 

 mother substance. Still further down, the crystals of Au.^Al 

 are scanty, and arranged in such regular patterns, generally in 

 lines at right angles to each other, as to render it certain that 

 they crystallised freely while surrounded by liquid. Finally, at 

 the bottom of the branch, that is at the eutectic point, the large 

 crystals of AujAl are absent, and the whole field is full of the 



mother substance, wiiicii is sometimes, but, as we explain in the 

 paper, not always a eutectic mixture. 



If, leaving the eutectic point, we ascend the next branch, 

 these phenonvena repeat themselves, but the primary crystallisa- 

 tion (that is the matter which solidified first) is now of a different 

 substance. 



The photograph reproduced is of an alloy which, taken as a 

 whole, would have the formula Au^oAlgQ. The darker part con- 

 sists of AugAl, which crystallised first. The lighter ground, or 

 mother substance, is in this case the pure body AU5AI2, and is 

 not a eutectic mixture. The pattern is typical of a point on the 

 curve situated a little way above a eutectic angle. (Magnifica- 

 tion 45 diameters.) 



Royal Microscopical Society, January 17.— Annual 

 meeting. — Mr. E. M. Nelson, the President, in the chair. — 

 The President announced with deep regret the death of the 

 Treasurer, Mr. W. T. Suffolk. He was an old member of the 

 Society, having joined it in 1863. In addition to acting as 

 Treasurer for some years, he had examined and catalogued the 

 slides, about 7700 in number, in the Society's cabinet, and had 

 remounted a great number of them, which had been found to be 

 leaking or otherwise imperfect. — A resolution expressing the 

 great sympathy of the Council with Miss Suffolk, and also 

 acknowledging her gift to the Society of her uncle's cabinet of 

 slides, was read to the meeting, and at the request of the President 

 the Fellows present endorsed the action of the Council by show 

 of hands. — After the report of the Council for the past year and 

 the statement of accounts had been read and adopted, the Pre- 

 sident announced that the following had been elected as officers 

 and Council for the ensuing year : —President : Wm. Carruthers ; 

 Vice-Presidents : A. W. Bennett, G. C. Karop, A. D, Michael, 

 E. M. Nelson ; Treasurer: J. J. Vezey ; Secretaries : Rev. Dr. 

 W. H. Dallinger, Dr. R. G. Hebb ; Ordinary Members of 

 Council : J. M. Allen, Conrad Beck, Dr. R. Braithwaite, E. T. 

 Browne, Rev. E. Carr, E. Dadswell, Sir Ford North. H. G. 

 Plimmer, T. H. Powell, C. F. Rousselet, Dr. J. Tatham, G. 

 Western ; Curator : C. F. Rousselet. — The President then de- 

 livered the annual address on the work done during the past 

 year in connection with the Society, including the standardisa- 

 tion of the substage and eye-pieces, and concluded by reading 

 a paper, which was a continuation of the optical subjects dealt 

 with in his previous addresses, and had special reference to the 



NO. 1580, VOU 61] 



aplanatic oil immersion front and the construction of the Huy- 

 ghenian eye- piece. — Mr. Michael proposed a vote of thanks to 

 the President, not only for the address, but also for his eminent 

 services to the Society during the time he had occupied the 

 chair. — In this period he had given a series of addresses which 

 will form an admirable record of the practical application of 

 the principles upon which the optical part of the microscope 

 was constructed. — Dr. Braithwaite having seconded the vote of 

 thanks to the President, it was put to the meeting, and carried 

 unanimously. — The President then introduced his successor, 

 Mr. Wm. Carruthers, who, having taken the chair, gave a short 

 address to the meeting. — Mr. Rousselet exhibited a mounted 

 specimen of Slephanoceros etchhorni, a rotifer which is very 

 difficult to kill with its cilia fully extended ; but after many 

 trials, Mr. Rousselet has succeeded in overcoming the diffi- 

 culty, and the specimen exhibited presented a very life-like 

 appearance. 



Linnean Society, January 18. — Dr. A. Giinther, F.R.S., 

 President, in the chair.— Mr. J. C. Hill, of Sydney University, 

 exhibited some photographs of specimens and drawings of 

 Monotreme and Marsupial embryos, obtained by him in 

 Australia. Of special interest were those of a newly-hatched 

 Ornithorhynchus, showing a nasal caruncle and the presence of 

 a medium maxillary tooth, the function of which is at present 

 undetermined. Chief among the Marsupial series were photo- 

 graphs of Dasyurus embryos in situ and showing the free 

 condition of the allantois. The Zoological secretary gave an 

 account of a paper by Mr. H. M. Kyle, incident to an extended 

 investigation of the flat-fishesnow progressing. The author records 

 in these and certain other Teleosteans the existence of " Nasal 

 Sacs," originally observed by Owen, and more recently by 

 Solger in the stickleback. He shows them to be secretory in the 

 less specialised Pleuronectidce, paired and non-secretory among 

 the soles. Mr. George Massee read a paper on the origin of the 

 Basidiomycetes. He remarked that Juel, a Danish mycologist, 

 had recently demonstrated that Stilbuni vulgare, hitherto 

 regarded as a typical Hyphomycete, is a true Protobasidiomy- 

 cete. Following up this hint, the majority of the species of 

 Siilbuin, some of which are the known conidial phase of species 

 of Sphaerostilbe, and others existing without any known higher 

 form, were examined, with the result that the conidial condition 

 of Sphaerostilbe microspora and S. gracilipes proved to be 

 identical in structure with Stilbum vulgare, in other words, 

 true Protobasidiomycetes. This discovery reveals the fact that 

 the conidial condition of an ascigerous fungus may {je a true 

 Protobasidiomycete. Similar discoveries had been made with 

 forms of Tubercularia and Isaria known to be the conidial 

 stages of ascigerous fungi. 



Manchester. 

 Literary and Philosophical Society, January 23. — Prof. 

 Horace Lamb, F.R.S., President, in the chair.— Mr. C. E. 

 Stromeyer read a paper on the origin of granite, in which he 

 suggested that, as the melting temperatures of solids are either 

 raised or lowered by pressure, and as the melting temperatures 

 of felspar and hornblende are certainly raised by pressure, it may 

 be found that the melting temperature of quartz is lowered 

 under such conditions ; if that were seen to be the case, a satis- 

 factory explanation would be afforded why the order of 

 crystallisation of granite-forming minerals is the reverse of the 

 order of their melting temperatures, because at the depths below 

 the earth's surface where these melting temperatures are reached 

 the pressures are sufficiently great to account for variations of 

 melting temperatures of several hundred degrees. Clerk 

 Maxwell even assumed that the melting temperature of these 

 minerals would be so materially raised that the earth's centre 

 must necessarily be solid. No experiments having as yet been 

 made on quartz, the author suggested that, if sufficiently small 

 specimens of this mineral were experimented upon in Prof. Joly's 

 meldometer, the molecular pressure — which for water is said to 

 be 5000 atmospheres— -would affect the melting temperature very 

 materially, and by this means the question as to the origin of 

 granite would be advanced one step. — A paper, entitled "Notes 

 on some Jurassic plants in the Manchester Museum," by A. C. 

 Seward, F.R.S., was communicated by Prof. F. E, Weiss. 

 The late Prof. W. C. Williamson collected from the inferior 

 oolite rocks exposed in the cliff sections south of Scarborough a 

 number of fossil plants, of which he sent drawings and de- 

 scriptive notes to Prof. Lindley, who figured a number of them 

 in the classic "Fossil Flora." Some of these plant-remains, now 



