March 25, 1886] 



NA TURE 



497 



The question whether electro-magnetic forces may not have 

 demonstrable action on natural, as well as polarised, light, has 

 been lately taken up by Herr Sohncke {WUJ. Ann. 2). His 

 guiding idea was this : — It is known that two polarised light- 

 rays from the same source, meeting at a sufficiently acute angle, 

 interfere most if they are polarised parallel, and not at all if 

 polarised at right angles, to each other. Now, natural rays of 

 light from the same source behave, in regard to interference, 

 quite like parallel polarised rays ; and it seemed likely that two 

 such rays would lose their power of interference if the direction 

 of vibration (or greater ellipse-axis) of one of them were turned 

 round by electro-magnetic forces 90" relatively to the other, for 

 in this case the two rays would behave like two polarised at 

 right angles to each other. This was effected (in a way he 

 describes). It appears that the same thing was done some years 

 ago by Prof Abbe, using with natural light the natural rotation 

 of a right and left quartz instead of electro-magnetic ; and this 

 before-unpublished method is also developed by Herr Sohncke, 

 who describes a new interference-experiment with natural light. 



Since Graham's time it has been generally accepted that thin 

 parchment paper is the best material for a dialyser. A variety 

 of substances have been experimented with lately by Herr Zott 

 in Munich (Wied. Ann. 2), and he pronounces goldbeaters' 

 skin the best ; it has always at least twice the separative effect 

 of parchment paper, and sometimes much more. In a list of 

 relative permeability, goldbeaters' skin being valued as I, we 

 have next, sow-bladder o'77, parchment paper o'5, 2 mm. 

 leather 0'025, and so on to the fifteenth, caoutchouc, o'oooi. 

 For solutions which injure organic membranes, common earthen- 

 ware cells (like those in Grove's battery) are best ; but their 

 effect is sixty to seventy-five times less than that of goldbeater's 

 skin. All phenomena of difl^usion are intensified, if the dia- 

 phragm is first evacuated in an air-pump ; and the more quickly 

 a substance dilTuses itself through a diaphragm, the greater is 

 the accelerative effect of evacuation. This evacuation should be 

 renewed after each experiment. It induces endosmose in dia- 

 phragms which did not previously show it ; and even colloids 

 show a considerable endosmose, even surpassing that of most 

 crystalloids if the time of diffusion is prolonged enough. Solu- 

 tion-mixtures of two substances are more easily and fully sepa- 

 rated the further apart their relative velocities of diffusion ; and 

 dialytic separation is more rapid the oftener the external water 

 is renewed. 



In a recent communication to the Erlangen Physical-Medical 

 Society Prof. Gerlach describes a successful method he has 

 devised for watching the embryo-growth in birds' eggs through a 

 small glass window made at the sharper end. After detaching 

 the end with a bent pair of scissors, a little albumen is taken 

 out, Eo that the germinal disk of the yolk turns upwards ; then 

 the liquid is put back. Gum-arabic solution is spread on the 

 opening, and wadding put round it ; then a small (ladies') 

 watch-glass is fixed on it with gum ; collodion and amber-lac 

 being afterwards added. The eggs must lie horizontally in the 

 incubator ; development then goes on normally, and may be 

 observed till the fifth day (thus comprising the time most inter- 

 esting to the embryologist), the egg being taken out and the 

 window-end turned up. 



The French language in Canada, according to M. Demanche 

 n a French review, presents no palois, owing to fusion of accents 

 by the well-educated teachers in schools, &c. , in the seventeenth 

 century, who came from all parts of France. Further, the 

 Canadian peasant is better educated than the French ; and all 

 French-Canadians speak English as well as French (an elevating 

 factor). In France, while foreign words are often adopted with- 

 out scruple, such as rail, -waggon, sleeping-car, tramway, ticket, 

 square, the French-Canadians generally translate, saying, e.g.. 



lisse, char, char-dortoir, char-urbain, billet, carre. The preser- 

 vation of the French tongue on the banks of the St. Lawrence 

 has been greatly favoured by the prodigious increase of the 

 French-Canadians. Of a total population of 4,324,819 by the 

 last census in 1S81, there were 1,298,929 French. The total 

 increase since the beginning of the century gives an annual rate 

 of 21 per cent., while the increase in the United States for the 

 same period is only 15 per cent, annually. In the province of 

 Quebec the French form four-fifths of the population. Celibates 

 are rare in Canada ; and families number, on an average, eight 

 to ten children, but sometimes one pair will give birth to 

 twenty-five children. A twenty-sixth child is educated at the 

 cost of the parish. 



A NUMBER of workmen were entombed in a subterranean 

 gallery at Chanulade (Dordogne) some time since. The work 

 for their recovery was so unfortunately protracted that all hope 

 of finding them ahve was lost for a long period. But it « as 

 deemed necessary to continue the excavation in order to procure 

 them a decent burial. This sad part of the programme could 

 not be executed with success. Then it was decided to excavate 

 a small hole and to use it for sending below an electric light and 

 a photographic apparatus to ascertain what was the condition of 

 the wrecked galleries. This operation was delayed by diffi- 

 culties but at last executed with complete success. A plate was 

 procured showing the likeness of a young man who had not been 

 crushed but who had evidently died of hunger. It is greatly 

 feared this fate has been shared by others of his unfortunate 

 companions. 



Although scientific researches on the habits of the herring 

 on the coast of Norway have been prosecuted almost without 

 interruption since 1861 (at the instance of the late Dr. Axel 

 Boeck), and some valuable results have been obtained there- 

 from, it is generally felt by those interested in this industry in 

 Norway that there still remains a great deal to be done in this 

 direction, as for instance has been the case in Scotland and 

 Prussia. This is chiefly applicable to the "summer" herring 

 visiting the shores of the provinces of Nordland and Tromso, 

 where hardly anything is known of the habits of the fish. It is, 

 therefore, proposed, in order to promote this important industry, 

 to prosecute scientific researches on the spawning of the fish, the 

 locaHties or fiords preferred by it for that purpose, the time of 

 the fish's coming inshore, and the climatic conditions most 

 advantageous to its existence. Considerable fresh light is also 

 expected to be thrown on this subject through the sea-water 

 fish-hatcbing establishment recently started at Arendal, in the 

 Christiania fiord. 



The additions to. the Zoological Society's Gardens during the 

 past week include a Macaque Monkey (Macaciis cynomolgus i ) 

 from India, presented by Mr. L. H. G. Morgan ; two Azara's 

 Opossums [Didelphys azane S 9 ) from Rosaria, La Plata, pre- 

 sented by Capt. G. W. Freeman ; three Striated Finches (.l/«;«'rt 

 striata), a Nutmeg Finch {Munia ptincttdaria), two Black- 

 headed Finches {Munia nialacca) from India, presented by Mr. 

 L. B. Lewis ; a Thunder Fish (Misgurttus fossUis) from Austria, 

 a Ground Loach (Cobites tcenia) from Russia, presented by Mr. 

 Alban Doran ; two Tasmanian Wolves {Thylacinus cyno- 

 cephaliis i 9) from Tasmania, two Red Kangaroos (Macropiis 

 riifus (5 9), a Great Kangaroo (Macroptis giganteiis) from Aus- 

 tralia, a Yellow-footed Rock Kangaroo {Petrogale xant/wptts), 

 two Haii7-nosed Wombats [Phascolomys latifrous (5 ?), two 

 Vulpine Phalangers {Phalangista vidpina), two King Parrakeets 

 (Aprosmictus scaptilatus), a Bauer's Broadtail {Platycercns zcna- 

 rius), two Swainson's Lorikeets {Trichoglosnts nova-hollandiie), 

 a Roseate Cockatoo (Cacatiia roseicapilla) from South Australia, 

 deposited ; a Bay Antelope {Cephalophus dorsalis 6 ) from West 

 Africa, a Green-billed Toucan {Ramphastos discolorus) from 



