566 



NATURE 



\Oct. 28, 1875 



been greatest (in the cases studied) on imbibition with water, less 

 with oil, and least with alcohol. It is greater the higher the 

 specific gravity of the liquid. The change of pitch with alcohol 

 and with oil was more regular than with water, and the regu- 

 larity was almost perfect, if the changes of tone of the saturated 

 bars were compared with one another, and not with the dry 

 state. — Herren Kundt and Warburg continue the account of their 

 researches on friction and conduction of heat in rarefied gases. 

 Having experimented with air, hydrogen, and carbonic acid, 

 they here show that the coefficients of friction are independent of 

 pressure within the limits 750 mm. and I mm. mercury. With 

 rarefaction under i mm. they could not sufficiently remove the 

 vapour. — Dr. Oberbeck describes a method of determining the 

 conductivity of liquids for electricity. The principle is briefly 

 this : — Connect the ends of an induction spiral with a spark micro- 

 meter. Then, with a certain strength of inducing current, a 

 separation of the balls may be found, at which sparks con- 

 tinuously pass ; but on slightly increasing the interval they cease 

 to pass. Next, connect the two ends of the spiral also with an 

 uninterrupted branch line ; it will depend on the resistance of 

 this and the intensity of the inducing current, whether sparks 

 will pass between the balls. If the line is short and of metallic 

 wire, the spark current disappears, however near together the 

 balls may be brought ; but if it consist of thin tubes of badly 

 conducting liquids,, a small approximation of the balls will 

 reproduce the sparks. Thus the conductivity of liquids may be 

 compared.' — An improved construction of lightning conductors 

 for telegraph-wires is described by M. Schaack. The line-wire 

 and that of the telegraph-apparatus are connected respectively 

 with two binding screws on pieces of wood which form opposite 

 rims of a rectangular tin case containing water, and a loose coil 

 of German silver wire, covered with caoutchouc, connects the 

 binding screws through the water. The wire of the telegraph- 

 apparatus, after passing through the apparatus, returns to the case, 

 which is connected to earth. — There is also an account of M. Le 

 Cour's valuable proposal for employment of tuning-forks in elec- 

 tric telegraphy. — M. Schneebeli continues his researches on the 

 attraction and separation-time of electro-magnets, and takes occa- 

 sion to describe Hipp's chronograph as recently improved.— 

 Among the remaining papers may be noted one by M. Sauer, 

 describing some interesting experiments on the visibility of ultra- 

 violet rays, and another by M. Holz, on transformation of 

 electric currents of low tension into disruptive discharges of 

 higher tension. 



Der Naturforscher, September. — This number contains some 

 interesting observations made at hot springs in Italy, by M. 

 Hoppe Seyler, on the upper temperature-limit of life. At Ischia, 

 on Monte Tabor, he found green algas on the widening sides of 

 a fissure through which rose hot steam, and the thermometer 

 showed 64° 7 C. This was higher than in the case of algse 

 growing in water ; at Lipari, the limit of temperature for such 

 seemed to be about 53°, — In a lecture by M. Brefeld (given in 

 outline), on the biology of yeast cells, the author describes the 

 process of fructification, which is asexual, and tells how all his 

 attempts to produce it with cultivated yeast were in vain ; with 

 the natural yeast used in fermenting wine he always succeeded. 

 — The peculiar condition of vegetation on the sides of lakes, and 

 banks of rivers, owing to reflection of light and heat from the 

 water, and constancy of temperature of the latter, is illustrated 

 by Dr. Hoffmann from a number of phgenological phenomena on 

 Lake Maggiore, the lakes of Geneva, Zurich, and other locali- 

 ties. — M. Felix Plateau investigates the process of digestion in 

 insects ; and M. Bohm records the gases resulting from fermen- 

 tation of dead marsh and water plants ; finding that these gases 

 sometimes consist of carbonic acid, nitrogen, and hydrogen, 

 sometimes of marsh gas with the first two. There is, he thinks, 

 a sort ot conflict between the two fermenting processes. — From 

 accounts of the aurora of Feb. 4, 1872, Donati is led to the striking 

 result that it was observed in different regions of the earth not 

 in the same physical moment, but everywhere at the same local 

 hour ; as is the case with celestial phenomena which do not 

 share in the earth's rotation. The aurora appeared first in the 

 extreme east of the southern hemisphere, in Eden and Mel- 

 bourne, and shortly after in China, whence it travelled over 

 Asia, Europe, and America. Donati attributes the phenomenon 

 to electro-magnetic currents from the sun. — There is also a paper 

 on the movements of Encke's comet, by Dr. von Asten ; and 

 among other subjects treated are : insular giant reptiles, diather- 

 mancy of moist air, beats of musical tones, and the formation of 

 meteorites and vulcanism. 



Zeitschrift der Oesterreichische Gesellschaft fur Meteorologies 

 Sept. 15. — The first paper in this number, by Herr Luedicke, 

 of Gotha, gives an account of observations made by him on the 

 tidal action of the moon in its several phases on the atmosphere, 

 during a period of 100 revolutions, from Jan. 1867 to Feb. 1875. 

 The differences between the mean heights of the barometer in 

 the four quarters are small; the greatest difference, viz., that 

 between the second and last quarter, amounting only to '57 mm. 

 The various tables given by Herr Luedicke agree, however, in 

 pointing to the following conclusion :— That pressure diminishes 

 with the waxing and increases with the waning moon. Com- 

 paring the means of readings nearest perigee with tliose nearest 

 apogee, he finds (i) that pressure is less at perigee than at 

 apogee ; and (2) that pressure in apogee is less about the time 

 of the equinoxes, greater about the time of the solstices, than in 

 perigee. Lastly, taking the mean variations from the monthly 

 mean of all observations taken in apogee and in perigee, that 

 in perigee the excesses happen at the quadratures, the deficiencies 

 at the syzygies ; and inversely, in apogee the excesses happen 

 at the syzygies and the deficiencies at the quadratures. These 

 variations are rather large : for instance, in apogee at the first 

 quarter the deficiency is 3 '83, at the last 5-16 mm. It appears 

 from all his results that the effect of the moon upon the atmo- 

 sphere is exactly ' contrary to that produced upon the ocean, 

 pressure being lower when the moon is near than when it is far 

 from the earth. Tables of the varieties of weather in the four 

 quarters are given at the end of the paper. — In the "Kleinere 

 Mittheilungen " two articles appear on Mr. Blanford's observa- 

 tions in India. 



Bulletin de VAcademie Royale des Sciences de Bel^ique, torn. xl. 

 No. 7. — In the "Classe des Science" are the following articles : — 

 A brief note by M. Emm. Liais, on the parallax of the sun. — 

 A note on Drosera rotundifolia, by M. Ed. Morren, to which is 

 a plate showing the structure of the different kinds of glands 

 and hairs. M. Morren describes the capture of two insects, and 

 especially draws attention to the way in which the glands curve 

 in "prehension," like an animal's tongue. — M. G. Dewalque 

 contributes a short article on lightning strokes. — M. E. Quetelet 

 records the dip of the needle at Brussels in 1875, determined on 

 two dates — 



April 14, between 10.30 a.m. and 12.30 = 66° 56' '6 

 May 22 ,, II ,, 12 =66° 58'-8 



The diminution is at the rate of 2\ min. per annum. The decli- 

 nation has been determined on three days as follows : — 

 June 9, between 11 a.m. and 12.30 = 17° 24'*4 

 „ 23 „ 10.30 „ 11.30 = 17' 25'-i 

 » „ „ 2 » 3 = 17° 26'-3 

 The decrease is 8j min. per annum. This last observation was 

 by M. Hooreman. — M. L. Saltel contributes two mathematical 

 papers. 



The yournal de Physique for September commences with a 

 paper by M. Marey on the movements of liquid waves in elastic 

 tubes, a phenomenon exemplified in the circulation of the blood. 

 He applies his graphic method : passing an indiarubber tube 

 through a series of boxes in such a way that when it expands at 

 successive points, through passage of a wave, it presses upwards 

 the membrane of one of the well-known monometric capsules. 

 These successive movements are indicated, as usual, on a rotating 

 blackened cylinder. He explains the various phenomena of 

 positive, negative, secondary, and reflected waves, harmonic 

 vibrations, &c. — M. Govi follows with an account of some experi- 

 ments meant to prove that induced electricity of the first kind has 

 tension. A new instrument for determining, more especially, 

 the density of solids of which only small fragments are had, is 

 described by M.'Paquet. It is like a Baume areometer, consisting 

 of a pear-shaped air-vessel, weighted at the lower, narrow end 

 with a bulb of mercury, while a thin tube rises from the upper 

 part, surmounted by a short wider tube closed below, into which 

 the solid fragment is put, with water. Both tubes are graduated. 

 The density is ascertained after immersion of the instrument in 

 water. — A valuable paper by M. de Romilly treats of the con- 

 veyance of air by a jet of air or steam, issuing from one ajutage, 

 and entering another ; several varieties of ajutage having been 

 experimented with, and in different positions. He finds, inter 

 alia, there is an integral conservation of the quantity of motion, 

 with a conical receiver of 5 to 7 degrees, small section towards 

 the jet-ajutage, which is placed at an exterior distance, given by 

 the form of the jet, making a cone of about 15 degrees, the jet- 

 orifice occupying the summit, and the receiver-orifice the base. 



