58 



NATURE 



{May 20, 1875 



other genera, appear to be formed upon a single t)rpe, contri- 

 butes naturally to the common opinion that the genus has few 

 but much-varying species. In describing the Greenland fo:ms, 

 Prof. Agardh has endeavoured to show that besides the differ- 

 ence in form, deviations also occur which ought to be retained 

 as characteristics. In a preceding memoir he had stated that 

 the differences noticed by other algologists in the antheridia and 

 spores being formed in the same or in separate receptacles may 

 possibly be explained thus : namely, that in different seasons the 

 receptacles ditiler in this respect. Should such an explanation 

 prove to be erroneous, it will undoubtedly be seen that it is these 

 differences, more .than others, that deserve to be considered as 

 the characteristics of species. 



The reader who wishes for further information relative to the 

 species of Algae inhabiting the Arctic seas is referred to the list of 

 Arctic Alga; in Harvey s Ner. Bor. Americana, and to Dr. 

 Dickie's List of Algae obtained in Cumberland Sound (Journal 

 of Linn. Soc. vol. ix.) Perhaps also some of the Algre collected 

 by Dr. Lyall on the north-west coast of America, thirty- two of 

 which had not been found elsewhere, may extend to the Arctic 

 Sea. See Harvey's List of AlgEC, collected by Dr. Lyall, Joum. 

 of Linn. Soc. vol. vi. 



Mary P. Merrifield. 



SCIENTIFIC SERIALS 



Atncrican Journal of Science and Arts , April, — The principal 

 contents of this number are : The history of Young's discovery of 

 his theory of colours, by Alfred M. Mayer. The aim of this 

 paper is to give extracts from Newton, Young, and Wollaston, 

 which embody the early literature of Young's celebrated theory 

 of colour, and to furnish a history of the steps by which he was 

 led to the adoption of what is now known as Young's theory of 

 colour- sensation. — A re-determination oi the constants of the 

 law connecting the pitch of a sound with the duration of its 

 residual sensation, by Alfred M. Mayer. This article refers to 

 a previous article of October 1874 on the same subject. Since 

 then, Madame Seller (who assisted Helmholtz) and Dr. Carl 

 Seller have spent considerable time in re-determining the dura- 

 tions of the residual sonorous sensations, using Mr. Mayer's 

 apparatus. From their experiments he has found the law 



given before as Z> = {. ^'^^ + 24)'oooi requires to be modi- 

 fied \.o D =■ —5^— -t- '0022, where D = the durations of the 



N -^ 31 

 residual sonorous sensation corresponding to N number of vibra- 

 tions per second.— On the action of the less refrangible rays of 

 light on silver, iodide, and bromide, by Carey Lea. The result 

 of 160 very concordant experiments shows that AgBr and Agl 

 are sensitive to all the visible rays of the spectrum. Agl is more 

 sensitive than AgBr to all the less refrangible rays and also to 

 white light. Ttie sensitiveness of AgBr to the green rays was 

 materially increased by the presence of free silver nitrate. AgBr 

 and Agl together are more sensitive to both the green and the 

 red rays than either Agl or AgBr separately.— On the Silurian 

 age of the Southern Appalachians, by F. H. Bradley. First 

 portion (to be continued). — Spectroscopic examination of gases 

 from meteoric iron, by Arthur W. Wright. On the supposition 

 that meteoric iron has received its hydrogen and other gases 

 from the sun or some other body having a similar atmosphere of 

 great density, it seemed probable that a spectroscopic examina- 

 tion might reveal the unknown gaseous elements assumed to be 

 present in the solar corona. Only negative results were obtained. 

 But the fact incidentally observed of the varying character of the 

 oxygen and hydrogen lines in the presence of hydrogen, and the 

 near coincidence of two of them with prominent coronal lines, 

 with the possible coincidence of a third line, goes to show that 

 the characteristic lines in the spectrum of the corona, so far from 

 indicating the presence of otherwise unknown elements, are 

 simply due to hydrogen and the gases of the air, oxygen and 

 nitrogen. — On the duplicity of the principal star of 2 1097, by 

 S. W. Burnham. — The original notes under the head of Scien- 

 tific Intelligence are : Progress of Geological Survey of Canada, 

 1873-74 ; the genera Opisthoptera (Meek, 1872) and Anoma- 

 lodonta (Miller, 1874) ; the Gulf of Mexico in the Miocene 

 time. 



Der Naturforscher, Nos. I to 5, 1875. — This part contains many 

 papers reprinted from other journals, besides several original 

 contributions. We note the following : — On the physiological 



action of amyl nitrite and the causes of blushing ; investigations 

 made by Herr Wilhelm Filehne, who found that amyl nitrite 

 acts upon that part of the brain which is also acted upon when 

 the individual has the feeling of shame and blushes. The most 

 interesting part of the paper is the description of the effects of 

 amyl nitrite upon animals ; accelerated breathing and palpita- 

 tions were the result, evidently similar to the physiological phc« 

 nomenon in man. In the latter case, whether produced by the 

 ether or by psychic emotion, the phenomenon is exactly the 

 same. — Report on the Crustacea observed on board the Challenger 

 between the Cape of Good Hope and Australia, in the Antarctic 

 seas, by Willemoes-Suhm. — On the ascending currents of air in 

 our atmosphere, by J. Hann, — On the finer structure of the 

 electric organs of fish, especially of the species Torpedo, Malap- 

 terurus, and Gymnotus, by F. Bol. — On the point of combus- 

 tion : a lecture delivered by A. Mitscherlich before the Chemical 

 Section of the Association of Naturalists at Breslau. — On the 

 fossil Cetacea of Europe, by J. F. Brandt— On the diatoms of the 

 coal age, by F. Castracane. The author succeeded in proving the 

 existence of diatoms in a piece of Lancashire coal ; it was pow- 

 dered finely, and burnt in a stream of oxygen. The residue was 

 treated with nitric acid and chlorate of potash, and then washed. 

 The species he found were all sweet-water species, with the 

 exception of a Grammatophora, a little Coscinodiscus, and an 

 Amphipleura, and comprised the following: — Fragilaria Harri- 

 sonii, Sm. ; EpUhemia gibba, Ehrbg. ; Sphenella glacialis, Kz. ; 

 Gotnphonema capitatum, Ehrbg. ; Nitzschia curvula, Kz. ; Cym- 

 bella scotica, Sm. ; Synedra vitrea, Kz. ; and Diaiovia vulgare, 

 Bory.— On the Chastopoda of the Atlantic, by E. Ehlers ; 

 account of the results of a collection made on board the Porcu- 

 pine in 1869. — Studies on the diameter of the sun, by P. Rosa. 

 These studies were published after the death of the author, by 

 Fathers Secchi and Ferrari, and contain many interesting details 

 which are well worth the attention of astronomers. — On the 

 absorption spectra of some yellow vegetable colouring matters, 

 by N. Pringsheim. The result of these investigations seems to 

 be that these colouring matters are merely modifications of chlo- 

 rophyll, and that there exist numerous modifications of thi» sub- 

 stance, from the brightest yellow to the darkest green. — On the 

 influence of the concentration of blood upon the motion of the 

 bl ot>i-corpuscles. 



SOCIETIES AND ACADEMIES 



London 

 Physical Society, May 8.— Prof. Gladstone, F.R.S., presi- 

 dent, in the chair.— Mr. Crookes, F.R.S., exhibited and described 

 some very important experiments on attraction and repulsion 

 resulting from radiation, which he has recently submitted to the 

 Royal Society, and of which an account has already been given in 

 this journal (vol. xi. p. 494). It is unnecessary therefore to de- 

 scribe them at length, but it may be pointed out that the most 

 beautiful of the instruments is one which Mr. Crookes calls a 

 radiometer. It consists of four arms suspended on a steel point 

 resting in a cup so that they are capable of revolving horizon- 

 tally. To the extremity of each arm is fastened a thin disc of 

 pith, lampblacked on one side, the black and white faces alter- 

 nating. The whole is enclosed in a glass globe, which is then 

 exhausted as perfectly as possible and hermetically sealed. 

 Several of these instruments varying in delicacy were exhibited, 

 and experiments made showing the influence of light and heat of 

 different degrees of refrangibility, and in proof of the law of 

 inverse squares, &c. — The President, in expressing the cordial 

 thanks of the Society, referred to Mr. Crookes' statement that 

 the repulsion was proportional to the length of the vibrations, 

 and asked whether at the red end of the spectrum there was an 

 abrupt termination of the action, and a gradual diminution 

 towards the ultra violet. — .Mr. Walenn inquired as to the action 

 of the magnet and of different axes of crystals in causing repul- 

 sion. — Prof. Woodward made some observations with reference 

 to the manipulation. — Prof. Guthrie paid a graceful compliment 

 to Mr. Crookes' work, and observed that researches might be 

 divided into two classes ; those in which the value of the work 

 outweighed the merit of the author, and those in which a result 

 of comparatively trifling significance is the outcome of years of 

 patient labour. He expressed a strong conviction that Mr. 

 Crookes' research had, in an almost unparalleled degree, both 

 elements of greatness. — Mr. Crookes stated, in reply to Dr. 

 Gladstone's question, that the glass envelope of the radiometer 



