\[ov. 23, 1876] 



NA rURE 



91 



iiount of solar radiation would necessarily vary inversely as the 

 nspot area, for at a period of maximum sun-spot area it was 

 issible that the radiation from the photosphere might be increased 

 such an extent as wholly to counteract the difference caused by 

 e decrease in the apparent area of the photosphere. He further 

 marked that the numbers given in his papers in conjunction • 

 th Messrs. Balfour Stewart and Loewy must not now be 

 lied upon, as some serious errors had been discovered which 

 was now endeavouring to put straight by a re-investigation 

 the whole subject. — Mr. Penrose read a paper entitled " An 

 ideavour to simplify the Method of making the Correction for 

 ! Spheroidal Figure of the Earth in Lunar Observations, and 

 rticularly with Reference to its Effect upon the Lunar Dis- 

 ice." — Mr. Christie described some observations which 

 had made with a polarising photometer upon the relative 

 ghtness of different parts of the disc of Venus. He had 

 ind that when the disc of Venus was gibbous, the last part of 

 : disc to disappear, as its brightness was decreased by rotating 

 1 photometer, was a sausage-shaped patch, the convex edge of 

 ich was found to be distinctly within the limb of the planet. 

 : thought that his observations supported Mr. Brett's theory 

 fto specula reflection from the surface of Venus. 



Linnean Society, November 2. — Prof. AUman, president, 



I the chair. — In exhibiting a live specimen of the Norwegian 



Imming, the survivor of seven at starting, Mr. Duppa Crotch 



I led attention to charts he had made showing the nature of the 



pund traversed in two instances in which he himself had wit- 



Ijsed the westerly migration of this singular little rodent. — Mr. 



I Bentham, vice-president, read a paper on the distribution of the 



jDnocotyledonous order into primary groups, more especially in 



lerence to the Australian flora, with notes on some points 



): terminology. — Dr. Francis Day drew attention to exami- 



jltions he had made on some Irish sticklebacks (Gasterostei). 



ese had led him to doubt the conclusions arrived by M. 



vage {No7iv. Archiv. d. Mus., 1874), as to the propriety of 



ding the family into subgenera and some seventeen species. 



Day has noticed such abnormal variations in the presence 



absence of ventral fin and spines in specimens of the three- 



ned and ten-spined sticklebacks as cause him to believe these 



ipendagestobe a very imperfect diagnostic and specific charac- 



H. Nay more, as certain other Acanthopterygians have been 



lierically divided by such features, it is questionable whether 



ther observations may lead to considerable necessary revision of 



: families. He is of opinion, moreover, that the spinal arma- 



e of at least the Gasterostei has an increment in the ratio of 



t:ir proximity and access to a maritime habitat. — Mr. H. W. 



J tes communicated a paper by Mr. D. Sharp on the respiratory 



i iction o\ the Carnivorous Water Beetles {Dytiscidce). Experi- 



I nts made by the author on numerous species show that there are 



I ie differences in the length of time they spend submerged and 



the surface for breathing exposure. For example, the Pelobiiis 



rtnanni rtmainsunder water in a ratio of 375 to I of air expo- 



e; whereas Dytiscus marginalis, a more highly developed 



m, has a corresponding ratio of about 12 to I. Most specimens 



the group are more active by night than by day. The 



Hirmamti and Hydrovatus clypealis he regards as much 



Is developed, and adapted for moving through the water than 



1 r indigenous water-beetles ; and therefore, along with the 



nerican Amphizoa, appear to him to represent the most rudi- 



tntary and primitive of existing forms of the Dyliscidse. — Prof. 



ckie gave a supplemental notice of Marine Algae obtained in 



! Challenger E-pedition. Of some fifty species one only is 



Iff. — A description of Thaumantis pseridaliris and Amesia pexi- 



da, two new Lepidopterous forms from Malacca, by Mr. A. 



itler, was taken as read. — The same author also had a com- 



mication on the genus Euptychia, a revision, with the addition 



twelve new species being made ; a case of these butierflies was 



hibited in illustration of his paper. — A second communication, 



Mr. D. Sharp, referred to new species of beetles {Scarabceida:) 



im Central America ; these had been captured by Mr. Belt, 



iefly in the neighbourhood of Chontales. — Mr. A. Peckover 



hibited and made a few remarks on two skins of the young of 



Madagascar insectivore, Hemicentetes niqriceps, Giinth., and 



a series of insects from the same island, collected by Mr. A. 



igdon, near Antananarivo. -^Mr. E. D. Crespigny showed a 



ecimen of the Umbelliferous plant, Tordylium maximum, L., 



tained near Tilbury Fort, a locality wliere it had disappeared 



■ a considerable length of time. 



Chemical Society, November 16. — Prof. Abel, F.R.S., 

 sident, in the chair. — A paper on barwood, by the late Prof. 



Anderson, was read by the Secretary, describing the method of 

 preparing baphuin from it, and also some of the educts obtained 

 by the action of various reagents. — The second communication 

 was on the alkaloids of the aconites. Part I. on the crystallisable 

 alkaloids contained in Aconitum napellus, by Dr. C. R. A. 

 Wright. The author finds that the alkaloids from A. ferox, 

 which he calls pseudanicotine, CjijH^gNOu, differs both in 

 properties and in composition from aconitine, C33H43NOJJ, the 

 crystalline alkaloid of A. napella. In one instance, however, he 

 obtained from the root of the latter a perfectly distinct bitter 

 crystalline alkaloid, picroconinite, possessing scarcely any toxic 

 power ; whether this is an alteration product of aconitine or not 

 remains at present undetermined. — Mr. G. S. Johnson then read 

 a paper on potassium triiodide, a crystalline compound obtained 

 on saturating a saturated solution of potassic iodide with iodine, 

 and slowly evaporating the solution over sulphuric acid. It 

 forms prismatic or tabular crystals having an appearance very 

 similar to that of iodine. — The last communication was by Mr. 

 T. S. D. Humpidge, on the coal-gas of the metropolis. He 

 has carefully analysed and determined the illuminating power of 

 different samples, and comes to the conclusion that the gas at 

 present supplied is but little if any better than it was twenty- 

 five years ago, the actual increase in illuminating power being 

 due to the use of improved burners. 



Physical Society, Nov. 4. — Prof. G. C. Foster, president, 

 in the chair, — The following candidates were elected members of 

 the society : — Warren de La Rue, D.C.L., F. R.S., and W. H. 

 Preece. — Dr. Guthrie read two letters which he had received 

 from Dr. Forel, in continuation of a communication which he 

 made to the Society on May 27 last, in reference to the " Seiches " 

 or periodic oscillations which take place in the Swiss lakes, and 

 on which he has recently made an elaborate series of observa- 

 tions. Since his communication he has found in a pamphlet by 

 Dr. J. R. Merian, published in 1828, a formula which is strictly 

 applicable to the phenomena under consideration. If t be the 

 duration of half an oscillation, h the depth of the lake, and / its 



_ ( '^ - I-M 1 

 I ^ I \e^ + e ' fS" 

 length, i = As/ — ) nh ~^ } Considering that pro- 

 bably this formula will be applicable to lakes of irregular depth 

 if k be the mean depth, he has applied it to several lakes, and 

 the following are some of his results. In the case of transverse 

 seiches on Lake Leman, the formula gives 216 metres as a mean 

 depth, and 334 metres is the greatest known depth. With a 

 longitudinal oscillation, the mean depth is found to be 130 

 metres. In the case of Lake Wallenstadt, the formula having 

 shown the mean depth to be somewhat greater than the 

 generally accepted greatest depth, Prof. Forel took a 

 number of fresh soundings, and found a great basin of com- 

 paratively even bottom and of such a depth as to render 

 probable the mean depth given by the formula. — Mr. O. 

 J. Lodge suggested that the formula would be rendered more 

 simple by using the hyperbolic function. It would then become 



/=7r /•- Coth — '. Mr. Lodge also indicated the curve 



V £ >■ 



which this equation represents. — Dr. Stone exhibited some dif- 

 fraction gratings on glass and metal, ruled for him by Mr. W. 

 Clark, of Windsor Terrace, Lower Norwood. The majority 

 of them were close spirals aljout 1,000 to the inch, which, when 

 held between the eye and a distant lime-light, exhibited circular 

 spectra of great brilliancy. The slight difference between the 

 spiral and true circles appeared to exercise no appreciable effect 

 on the result. The metal gratings were of linear form, 1,000 

 lines to the inch, intended for use by reflection in a spectroscope. 

 The spectra thus obtained were of much greater brilliancy than 

 those ordinarily obtained by refraction, and presented obvious 

 advantages for examining the ultra-violet rays. He explained 

 the mechanical difficulties which had been surmounted in 

 their manufacture together with the manner in which the 

 diamond cutters are prepared. The metals hitherto employed, 

 namely, cast-steel and German silver, are objectionable, and 

 Dr. Stone proposes, on the suggestion of Prof. McLeod, 

 to employ speculum metal, and will report the result of 

 the experiments more fully at a subsequent meeting. — Dr. 

 Guthrie then briefly described some experiments which he has 

 made to determine the effect of a crystalloid on a colloid when 

 in the presence of water. Mr. Graham, in his classical re- 

 searches, made numerous experiments witii a salt on one side of 



