94 



KNOWLEDGE. 



[May 1, 1898. 



A set of rules for estimating the quality of vulcanized 

 caoutchouc have been drawn up by M. Vladimiroft, and 

 are adopted in Russian naval stores. Briefly, the criteria 

 are as follows : — (1) Caoutchouc should not give the least 

 sign of cracking when bent to an angle of 180°, after five 

 hours' exposure in an air bath at 125° C. (2) Caoutchouc 

 having not more than half its weight of metallic oxides 

 should tear stretching five times its length before lupture. 

 (3) Caoutchouc, exempt frcm all foreign matter except 

 tulphur, should be capable of stretchirg at least seven 

 times its length before rupture. (4) The extension 

 measured just after rupture should not escetd twelve per 

 cent, of the original length. (5) Suppleness may be 

 determined by calculating the percentage of ash after in- 

 cineration. This may foim the basis of choice for certain 

 uses. (6) Vulcanized caoutchouc should not harden in 

 cold. 



Astronomy and Astro-Physics (for April) says that Mr. 

 James E. Keeler has made a series of obEer\ations of the 

 spectrum of the interesting variable star /3 Lyrse, using 

 the Lick Observatory 36-inch telescope. The foJlowinj.' 

 conclusions seem to be warranted by the observations :— 

 (1) In the spectium of /3 Lyrse the bright hydrogen lines 

 C and F, the bright D3 line, and the dark D lines are 

 constantly visible with a telescope as large as the Lick 

 refractor. Certain fainter bright lines become invisible at 

 the time of a principal minimum. (2) The variations in 

 the light of the star are principally cue to changes in the 

 brightness of the continuous spectrum. (3) The bright 

 lines are brightest when the continuous spectrum is 

 brightest. (4) The bright lines are broad and difiuse, 

 particularly when the star is at a maximum. The D lines 

 are very hazy, so that the components are hardly 

 distinguishable. (5) During the greater part of the period 

 of the star no remarkable changes occur in the appearance 

 of the spectrum. The observations fail to show any 

 connection between changes in the spectrum and the 

 secondary minimum of the star. (6) Tl e most remarkable 

 changes take place at the time of a piincipal minimum. 

 The bright lines become dimmer, and perhaps sharper, 

 and the fainter bright lines disappear. The D lines 

 become darker. Strong absorption lines appear on the 

 more refrangible side of certain bright lines in the green, 

 the separation of the dark and bright lines being at least 

 five-tenth metres. Other bright lines are perhaps similarly 

 affected. A narrow dark line appears above the D3 line at 

 the same time. Shortly before the first maximum is 

 reached the dark lines disappear. 



DEEP SEA DEPOSITS. 



By Rev. H. N. Hutchinson, B.A., F.G.S., Author of 

 " Extinct Monsters," dr. 



[Third Papbh.] 



WITH the exception of the red clay, described in 

 our last paper, the famous t/lohii/crinii ooze is 

 the most widely distributed of all marine 

 deposits. It occupies the greater part of the 

 Atlantic, and a good deal of the Indian, 

 Pacific, and Southern Oceans. Its total area is estimated 

 at 49,520,000 square miles. Examination of Chart I. (p. 

 44j shows that it occupies all the medium depths of the 

 ocean removed from continents and islands, and that it 

 is especially developed in those regions where the surface 

 of the sea is occupied by warm currents. The patch in the 

 Norwegian Sea is evidently due to the northward extension 

 of the Gulf Stream. The first specimens of this ooze were 



obtained by Lieut. Berryman, United States Navy, in the 

 North Atlantic, and were described in detail by Ehrenberg 

 and Bailey in 1858. 



As we have before remarked, there is a difficulty in 

 drawing hard and fast lines on a chart to mark off the 

 geographical areas of one deposit from those of another ; 

 and the reasen of this is that to seme extent they merge 

 into each other. The question is, where to draw the line. 

 For example, were all deposits containing only ten or 

 fifteen per cent, of foraminifera to be classified as globi- 

 gerina ooze, then this deposit wou'd be found to be by far 

 the most widely distributed of all the deep sea deposits. 

 In all types of marine deposits, and in all latitudes, some 

 species of these shells are present in gieater or less 

 abundance. '21^ 



Messrs. Murray and Renard, however, draw the line at 

 thirty per cent, or more of carbonate of lime ; and any 

 deposit having so much lime, or more, is put down in their 

 report as globigerina ooze. There was at one time a good 

 deal of uncertainty as to whether the foraminifera that 

 chiefly go to make up the lime in this deposit lived at the 

 surface or on the sea floor ; but, after some years of doubt, 

 it has been definitely settled that most of them lived at or 

 near the surface. To those who are familiar with the 

 protozoa it may be interesting to know that among the 

 pelagic foraminifera taken in surface nets during the cruise 

 of the Challenyer were : globigerina (ten species), orbulina 

 (one species), pulvinulina (five species), hastigerina* (one 

 species), pullenia (one sptcies). The majority of these 

 species are limited to those deposits immediately under 

 warm tropical waters, and only a few of them were met 

 with in deposits dredged up from the colder regions of the 

 ocean. 



The Challenger naturalists found the deposit ranging in 

 depth from 400 to 2925 fathoms (giving an average depth 

 of 2002 fathoms) ; 118 samples were examined. We may 

 say that it is most typically developed at 2000 fathoms. 

 At greater depths than 2500 fathoms the carbonate of lime 

 is gradually removed, the ooze becoming darker in colour 

 until finally it gives place to a red clay. In the Atlantic, we 

 find it covering the submarine ridges and elevated plateaux, 

 and it borders the upper zone of the oceanic abysmal 

 area. Its prevailing colour, far from land, is milky white 

 or rose colour, and near land, dirty white, blue or grey. 

 Sometimes it has a mottled appearance, due to the presence 

 of manganese grains, volcanic ashes, pumice, &c. In 

 tropical regions, where warmth favours growth, the forami- 

 nifera are often large enough to be visible to the naked 



* Extract from Wyvillk Thomson : — '' The Atlantic." ^ 

 Vol. ir., p. 293. 

 62(7., Living Hatttigerina, — "On one occasion, in the Pacific, wlien 

 Mr. Murray was ont in a boat in a dead calm collecting surface 

 creatures, he took gentlj up in a spoon a little globular gelatinous mass 

 with a red centre, and transferred it to a tnlic. This globule gave us 

 our first and la?it chance of seeing what a pelagic foraminifer really ia 

 when in its full beauty. When placed under the microscope, it proved 

 to be a hastigerina in a condition wholly different from anything which 

 we had yet seen. The spines, which were mostly unbroken, owing to 

 its mode of capture, were enormously long, about 15 times the diameter 

 of the shell in length ; the sarcode, loaded with its yellow oil-cells, 

 was almost all outside the shell ; beyond the fringe of yellow sarcode 

 the space between the spines, to a distance of about twice the diameter 

 of the shell all round, was completely filled up with delicate bulhe, like 

 those which we see in some of the Badiolarians, as if the most 

 perfectly transparent portion of the sarcode had been blown out into a 

 delicate froth of bubbles of uniform size along the spines ; fine double 

 threads of transparent sarcode, loaded with minute granules, coursed 

 up one side and down the other, while between the spines, independent 

 thread-like pseudopodia ran out, some of them perfectly free, and 

 others anastomizing with one another or joining tlie sarcodic sheaths 

 of the spines, but all showing the characteristic flowing movement of 

 living protoplasm." 



