390 



NATURE 



{Sept. lo, 1874 



of citric acid, and of alumina or iron oxide, introduces sources 

 of error. 



Oil an Im proved Form of filter Pump, by W. Jesse Lovett. — 

 This pump, which is very simple and ajipears to give good re- 

 sults, has already been described in tlie CItemical News. 



On Sulphur- Uren, by Prof. Emerson Reynolds. — By heating 

 dry ammonium sulphocyanate, sulphur-urea — as has been before 

 shown by the author — is obtained. If the heat be maintained 

 at 1 70°, about 26 per cent, of urea is obtained in one hour. By the 

 action of metallic oxides in solution on sulphur- urea, metallic 

 sulphides are obtained, together with cyanamide, which, by the 

 pro'onged action of water, is changed into dicyanamide. 



On the jfoint Action of Carbonic Acid and Cyanogen on Oxide 

 of Iron, and on Metallic Iron, by Lowthian Bell, F.R. S. — -The 

 author shows that a mixture of carbonic acid (CO.,) and cyano- 

 gen exercises a powerful reducing action at a liigh temperature 

 upon ferric oxide. With one volume of cyanogen and six 

 volumes of carbonic acid at a temperature of 685° to 710° F., 

 79'9 per cent, of the oxygen existing in comliination with iron 

 was removed, 56 '3 per cent, of metallic iron being produced ; 

 by increasing the proportion of carbonic acid to fifteen volumes, 

 65 per cent, of metallic iron was produced, while 'g per cent, 

 only was formed when the carljonic acid amounted to thirty 

 volumes. A certain amount of carbon is simultaneously de- 

 posited in the reduced iron. The reducing and carbon deposit- 

 ing power of a mixture of cyanogen and carbonic acid is greater 

 than that of a mixture of carbon monoxide and carbonic acid. 



Electrolytic Experiments on Metallic Chlorides, by Dr. Glad- 

 stone, F. R.S., and Mr. Tribe. — The authors show that if 

 plates of copper and platinum be immersed in a dilute 

 solution of cupric chloride, a current is obtained from the 

 copper to the platinum, the cupric chloride is broken up 

 into cuprous chloride and chlorine, the former being deposited 

 on the platinum, while the latter combines with some of 

 the copper to form a new cupiic chloride Cu -^ CuCI„ = 

 2 (CuCl). By applying an external current the same action takes 

 place ; if, however, the strength of the current be increased, the 

 free chlorine makes its appearance. By substituting zinc for 

 copper a greater effect is obtained ; with magnesium in the place 

 of zinc, tlie effect is still greater. Analogously to the foregoing, 

 a current may be obtained by acting on a solution of mercuric 

 chloride with gold and mercury, whereby mercurous chloride is 

 deposited on the gold. 



Composition of certain kinds of Pood, by W. J, Cooper. — 

 Tlie author drew attention to the nourishing properties of 

 farinaceous foods, such as arrowroot, corn flour, &c. Such fooJs 

 he believes very well suited for infants and invalids. He holds 

 that we generally take too mucli nitrogenous substance in our 

 dietaiies. 



SECTION C— Geoi.oi-.v 



Prof. Harknes.c, at the request of the Committee of the Sec- 

 tion, described briefly the geological features of the North 

 of Ireland. The relations of the Silurian rocks to the Lower 

 Silurians of Sutherland.Aire and Cumberland were discussed, and 

 the later formations were noticed in succession. 



Prof. H. A. Nicholson exhibited and described a silicified chip 

 of wood from the Rocky Mountains. At the Brighton meeting 

 the same specimen was shown, when the opinion was expressed 

 that its wood-like appearance was due to mineral structure. The 

 chip was then regarded by some members of llie Section as a 

 hornblendic mineral, known as "rock-wood." .Subsequent exa- 

 mination has shown conclusively that the specimen is undoubtedly 

 true silicified wood. The age of the chip and the circumstances 

 of its production present many points of interest. The author 

 considers it a prehistoric relic, produced by an axe, which was 

 probably formed out of the native copper so frequent in various 

 paris of North America. 



Prof. Harkness accepted the views of the author, and with- 

 drew his previous opinion that the specimen was merely a horn- 

 blendic mineral. 



SECTION D— BlOLO Y 



Department of Zoology and Botany 



Mr. Gwyn Jeffreys read a paper On additions to British 



Mollusca, and notices op rare species from the deep water off the 



■western coast of Ireland. As many as forty-seven species of 



molluscs new to science have been yielded as the results of the 

 dredgings in the Porcupine, eighty-four new to the British Isles, 

 and 124 new to Ireland, in addition to a number of other species 

 hitherto considered to exist only in the fossil condition, some of 

 them as low down as the Crag. Dr. Carpenter called attention 

 to the enormous importance of these dredging expeditions, not 

 so much from the number of new species discovered by them as 

 from the light which they seem likely to shed on the question of 

 the con^nuity of forms of life from one geological age to another. 

 The dredgings off Ushant at a depth of nearly three miles have 

 been especially prolific of results. Dr. Caq^enter held out some 

 hopes that the Government miglit be induced to undertake the 

 expense of a dredging expedition in our own deep seas. 



Mr. P. L. Sclater read a paper On the distribution of the species 

 of Cassowaries. Until very recently there was supposed to be 

 only one species of Casnarius ; now at least se\ en species are 

 known, each with a distinct and very limited area, the genus 

 lieing entirely confined to Northern Australia, New Guinea, and 

 tlie adjacent isles. A full exploration of New Guinea would 

 probably lead to the discovery of a large number of most inte- 

 resting new species. 



On the cause of the potato disease and the means of its prevention, 

 by Mr. J. Torbitt. The idea thrown out in the paper was that 

 the dise.ase is owing to the gradual natural decay of particular 

 varieties which never have more than a limited length of life in 

 a thoroughly healthy condition, a view which was combated by 

 most of tlie gentlemen who took part in the discussion. Mr. 

 Carruthers described the mode in which the spores of the Perono- 

 spora germinate in enormous numbers on the surface of the potato 

 plant, the germinating filaments, however, only developing to a 

 very limited extent and dying away unless abundantly supplied 

 with moisture. It is only by this means that they are enabled to 

 penetrate into the internal tissues through the stomates. Prof. 

 IJu Barry's recent researche; seem to point to the possibility that 

 we have in the Pironospora an ins'ance of " alternation of gene- 

 rations," one generation only being at present known, the other 

 generation possibly presenting an altogether different appearance, 

 and germinating upon some totally different plant. 



Prof. Macalister read Notes on the specimen of Selache ma.ximus 

 lately caught at Innisboffn. 



Further Researches on Eozoon canadense, by Dr. Carpenter. 

 After an historical account of the controversy respecting this 

 organism, the author proceeded to give additional reasons, the 

 results of recent investigations, for concluding the organic nature 

 of the organism, in opposition to the views entertained by Profs. 

 King and Rovvney, of Galway. He took the opportunity of con- 

 tradicting the assertion made by those gentlemen that Prof. Max 

 Schultze had just before his death stated his conversion to their 

 views. Mr. Gwyn Jeffreys, Prof. Macalister, and Prof. Percival 

 Wright expressed their general concurrence in Dr. Carpenter's 

 views. 



SECTION G 

 Mechanical Science 



Opening Addres.s by the Prestdent, Prof. James 

 Thompson, LL.D. 



For a number of years past it has been customary in this andf 

 other sections of the British Association for the Advancement os 

 .Science, that the president should give an introducloi-y addrest 

 at the opening of each new ses^ion. In compliince with than 

 usage, I propose now to of^er to you a few bri;f remarks Oe 

 various subjects of mechanical science and practice. Thea^. 

 subjects have not been chosen on any systematic plan. I hav^ 

 not aimed at bringing under review the whole or any largj- 

 number of the most important subjects at present worthy o 

 special notice in engineering or in mechanics generally. I intend 

 merely to speik of a few matters which have happened to come 

 under my notice, 01 have engaged my attention, and which 

 appear to me to be interesting through their noselty or through 

 their important progress in recent times, or to merit attention as 

 subjects in which amendment and future progress are to be 

 desired. 



In railway engineering, one ot the most important topics for 

 consideration, as it appears to me, is that which relates to the 

 abatement of dangers in the conducting of the traffic. The 

 traffic of many of our old railways has become enormously in- 

 creased in recent years. With the construction of new lines the 

 numbers of junctions, stations, and sidings have been greatly in 



