April 18,1872] 



NATURE 



493 



the Primordial Fauna much farther west than it had been found 

 before.— Prof. Dana's notice of the addv..-ss of Prof. T. Sterry 

 Hunt, before the American Association at Indianapolis has 

 already appeared in cxtciiso in our columns. — Prof. Roland Irving 

 on the age of the Quartzites, Schists, and Conglomerates of 

 Sauk Co., Wisconsin, holds them to be unquestionably islands 

 in the Potsdam Sea, famishing beiutiful illustrations of wave 

 action on a rocky coast. — Prof Hayden gives an extremely in- 

 teresting account, dlustrated by maps, of the hot springs and 

 Geysers of the Yellowstone and Firehole Rivers, the result of the 

 recent Government exploration of that district. Prof. T. Sterry 

 Hunt continues his notes on granite rocks, and Mr. A. S. VerriU 

 his contributions to Zoology from the museum of Yale College. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, April 11.— " Researches on Solar Physics." 

 —III. By Warren De La Rue, F.R.S., Balfour Stewart, 

 F.R.S., and Benjamin Loewy. 



The authors present in this paper the third instalment of the 

 determination of the areas and heliographic positions occupied 

 by the sun-spots observed by the Kevv photoheliograpli, com- 

 prising the years 1S67, 1S6S, and 1S69. They announce that 

 the fourth and last instalment is in active progress, and will be 

 preceded by the final discussion of the whole ten-yearly period, 

 during which the pholoheliograph has been at work. This final 

 discussion will contain the determination of the astronomical 

 elements of the sun on the basis of photographic observations, 

 and this work they anticipate will not only settle the question of 

 rotation for a conbiderable time to come, but will also throw 

 light upon many points which have only recently been brought 

 under the consideration of scientific men. The results in gene- 

 ral, they believe, will prove the superiority of photographic sun- 

 observations over previous methods. The second question 

 which wi 1 be discussed is the distribution of sun-spots over the 

 solar surface. The tacts already brought out indicate that the 

 progress of the inquiry may lead to some definite laws which 

 regulate the distribution ; there appear to exist centres of great 

 activity on the sun, and the different solar meridians seem to 

 have various but definite intervals of rest and activity. In con- 

 clusion the authors point out the necessity of devoting in future 

 greater attention to the study of the facuh-e, and express a hope 

 of seeing photographic sun-obstrvations carried on in this 

 country on a more extended system, connecting from day to day 

 solar phenomena with terrestrial meteorology and magnetism. 



Correction to Messrs. De La Rue, Stewart, and Loewy's 

 papers " On some recent Researches in Solar Physics, &c." 



The erroneous date given in our paper for one of Professor 

 Wolf's maxima has already been corrected by us, and we give in 

 the subjoined httle table the corrections of the tew numerical 

 data which are necessitated by the error of fixing the date of 

 masmum at 1S46 6 instead of 1 848 '6. 



Prof. Wolf's ratio % (p. 86). 



I. 1-265) —0728 1-2651 +0-283 



II. 2-615 > Mean 2-093 -1-0-522 i -478 > Mean i -548 +0-073 

 111.2-400) +0-307 1-900) +0-352 



The differences derived from our own results are respectively 

 + o-o6i, and —0-047, *^t '5' t'^'^y '^'■^ ^'''^ much smaller, and 

 agree singly better with the mean, than if Prof Wolf's ratio 

 were adopted ; hence our conclusion is quite unaffected by this 

 correction. 



The remark made by us with reference to this maximum 

 will remain in force even -with the corrected date. We stated 

 there that this particular maximum showed alone an appreci- 

 able difference from the dates fixed by ourselves, for it will 

 be found that Prof Wolf's date differs still by about three- 

 quarters of a year from ours. 



" Contributions to the History of the Opium Alkaloids." — 

 Part V. By Dr. C. R. A. Wright. 



" The Action of Oxygen on Copper Nitrate in a state of 

 Tension." By Dr. J. H. Gladstone, F.R.S., and Alfred 

 Tribe, F.C.S. 



In our experiments on the action between copper and nitrate 



of silver in solution, we frequently noticed that the tips of the 

 silver crystals became red, as though coated with a thin layer of 

 metallic copper. 



This apparent deposition of a positive on a more negative 

 metal of course raised our curiosity, and led us to look closely 

 into the circumstances under which it occurred. We found that 

 it took p'ace only when the nitrate of silver was exhausted, and 

 only on those silver crystals which remained in metallic connec- 

 tion with the copper. We found, too, that the cupreous coating 

 formed most readily where air liad the freest access ; and, in 

 fact, that it would not form at all in vessels from which oxygen 

 was excluded, nor on those white crystals which were far below 

 the surface of the liquid, though they might be in immediate 

 contact with the copper plate. When an inverted jar was filled 

 with nitrate of copper solution and silver crystals resting on 

 branches of copper, and the liquid was displaced by oxygen gas, 

 it was found that the tips of the crystals became red, and the 

 solution gradually filled the jar again by the absorption of the 

 gas. In the same way the oxygen was absorbed from air, or 

 from its mixtures with liydrogen or carbonic anhydride. This 

 action was further studied by employing plates of the two metals 

 instead of copper covered with silver crystals. When the two 

 plates, connected by a wire, were partially immersed in an ordi- 

 nary aqueous solution of copper nitrate, it was found that a 

 slight yellowish deposit made its appearance speeddy all over the 

 silver plate, and went on increasing for a day or two, while at 

 the air line there was a thicker deposit, which gradually grew 

 and extended itself a little below the surface. This deposit 

 changed from yellowish to red, and under the microscope pre- 

 sented a distinctly crystalline appearance. Thinking that this 

 slight crust all over the silver plate was due to the air dissolved 

 in the solution itself, we took advantage of the reaction to pre- 

 pare copper nitrate absolutely free from dissolved oxygen. An 

 ordinary solution of the salt mixed with some silver nitrate was 

 placed in a narrow cylinder, with a long piece of copper foil 

 arranged somewhat spirally so as to retain the deposited silver 

 on its surface, and allowed to rest for twenty-four hours. 



The solution thus obtained was exposed to the action of the 

 conjoined copper and silver plates, but even after some hours 

 there was no diminishing of the lustre of the silver plates, except 

 at the air line, which was sharply defined. The same solution 

 shaken for some time in the air produced a yellowish deposit on 

 the white metal in three minutes. 



The colour and gener.U appearance of this crust, together 

 with its formation only where oxygen can be absorbed, showed 

 that it was not metallic copper, but the suboxide. 



This was further proved by the action of diluted sulphuric 

 acid, which resolves it at once into red metallic copper and cop- 

 per sulphate. There is also another curious reaction which can 

 only be properly observed under a microscope. 



When treated with a solution of silver nitrate, this cupreous 

 deposit does not give the ordinary crystals of the white metal ; 

 in fact, it is only slowly acted upon, but presently there shoot 

 forth thin threads of silver which run through the liquid, often 

 twisting at sharp angles, whde the yellowish crystals change to 

 black. This also was found to be a property of the suboxide of 

 copper. This deposition of oxide on the silver is accompanied 

 by a corresponding solution of copper from the other plate. 



Thus, in an experiment made with nitrate of copper solution 

 that had been exposed to air, and which was allowed to con- 

 tinue for four days, there was found — 



Gain of silver plate, o-oi6grm. 

 Loss of copperplate, 0-015 grm. 



The copper necessary for the production of o -016 grm. of 

 suboxide would be a little above 0-014 g'''"- 



The wire connecting the two plates in this experiment is 

 capable of deflecting a galvanometer. The current takes place 

 from copper through the liquid to silver, that is, in the same 

 direction as if the copper had been dissolved by an acid, and 

 hydrogen evolved on the sdver plate. 



If the two plates have their sides parallel, the suboxide is 

 deposited not merely on that side of the silver plate which faces 

 the copper, but after about a minute on the other side also, 

 showing that in this, as in other cases, the lines of force curve 

 round. 



It became interesting to consider what started this electric 

 current. The original observauons convinced us that it was not 

 due to the action of oxygen on the copper ; but to make the 

 matter more certain, bright copper and silver plates in conjunc- 



