April 24, 19 19] 



NATURE 



53 



The Origin of Nov^.— Prof. W. H. Pickering 

 examines various theories of the origin of novae in 

 Popular Astronomy for November last. He rejects the 

 theory of collision of star with star on the grounds 

 that novae are too numerous for this and that the 

 period of brilliance is too short. The first difficulty, 

 but not the second, is avoided by the theory of col- 

 lision of star with nebula ; it would probably require 

 years, not days, for a star, even at the enormous 

 speed indicated by the spectroscope, to traverse a 

 nebula of average size. Prof. Pickering prefers the 

 hypothesis of a body of small planetary dimensions 

 falling into the star and penetrating the photosphere 

 to some depth before it exploded. He pictures its 

 conversion into gas as being so rapid and violent as 

 to scatter the materials of the photosphere to a con- 

 siderable distance all round, thus producing an im- 

 mense, but short-lived, increase of light. He notes 

 that he is drawing on the star's own energy for the 

 outburst, the falling planet merely acting as the 

 trigger. The dark and bright bands of the spectrum 

 are explained (as on many other theories of novae) 

 by the outer shells of gas being cooler, and so ab- 

 sorbing light, while the light from the gases streaming 

 out on the remote side of the star, having its wave- 

 length altered by motion, Ts not arrested by the cool 

 gas on the near side. Newcomb, in "The Stars : .\ 

 Study of the Universe " (p. 138), suggested a similar 

 explanation, treating the stars as hollow globes of 

 highly heated and condensed gas ; a foreign body, on 

 failing, might break the shell, when the interior gase> 

 would burst forth. "What magnitude the outburst 

 might assume it is impossible to say." 



Celestial Systems. — ^The Memoirs of the College 

 of Science, Kyoto University (vol. iii., No. 7), con- 

 tain a paper by Shinzo Shinjo and Yoshikatsu 

 Watanabe on the angular momenta of celestial 

 systems. The authors examine all the binary and 

 multiple systems for which sufficiently accurate data 

 are available (including eclipsing variables). They 

 show that the resulting momenta are confined within 

 tolerably narrow limits, and exceed several hundred- 

 fold the angular momentum of the solar system. In 

 studying the possible origin of angular momentum 

 thev examine the case of a spherical swarm of 

 meteorites, and show that, for a given mass, the 

 larger the individual meteorites the greater the 

 probable momentum. To produce the momentum of 

 the solar system they conclude that the individual 

 meteorites must have been about 20 km. in diameter. 

 The size would require to be much larger to satisfy 

 the conditions of the binary systems. It is conjec- 

 tured that swarms with the largest meteorites would 

 condense into two or more nuclei, those with medium- 

 sized meteorites into single orbs which would 

 afterwards divide into two, those with meteorites 

 20 km. in diameter into planetary systems. In the 

 case of dust-swarms or gaseous nebulae, the number 

 of constituents is so immense that the resulting 

 angular momentum is infinitesimal. While the paper 

 does not give a complete system of cosmogony, it 

 sheds fresh light on some of the stages of the process. 



COTTON 'SEED BY-PRODUCTS. 



ON February 5, at the Roval Society of Arts, 

 Mr. Ed. C. de Segundo read a very interesting 

 and suggestive paper on "The Removal of the 

 Residual Fibres from Cotton-seed and their Value 

 for Non-textile Purposes." Mr. de Segundo explained 

 that there are two main classes of cotton-seed, viz. 

 the bald, black, or clean seeds, such as Egyptian, 

 Sea Island, Brazilian, etc., of which practically the 

 whole "lint" is removed by the process of "ginning," 



NO. 2582, VOL. 103] 



or separating the lint or textile fibre from the seed; 

 and the white, woolly, or fuzzy seeds such as 

 American, which are still covered with a short white 

 •fuzz" or lint after ginning. Indian cotton-seed is 

 really of the latter class, though the fuzz remaining 

 on the seed is much shorter than in the case of the 

 American. 



To deal with these two classes of seed, two different 

 methods have been adopted. The black seeds are 

 crushed whole, and the residue after extraction of the 

 oil is pressed into cattle-cake. The white seeds are 

 first "delinted," which removes part of the short fuzz 

 left on the seed after ginning, the machine used being 

 practically the same as the saw-gin used for the 

 ginning itself. The short fuzz or "linters" thus 

 removed is used for guncotton, blotting-paper, waste, 

 etc. The seed is then "decorticated," a process of 

 separating the hull, with the fuzz still remaining on 

 it, from the kernels or meats. The latter are then 

 crushed alone, and the oil is taken out in a much purer 

 form than is possible under the whole crushing pro- 

 cess, because the presence of the hull or shell gives 

 a darker colour to the oil. Incidentally, the process 

 afterwards required to remove this dark colour gives 

 the oil a slightly bitter taste, which made the value 

 i of such oils distinctly lower than those got by the 

 I decorticating process. The crushed kernels give a 

 I very fine residual product known as cotton-seed meal, 

 which has recently been attracting particular atten- 

 tion because it has been shown to possess very high 

 qualities as human food. Its protein and fat contents 

 are very high, and mixed with potato- or wheat-flour 

 it produces a most valuable form of food. 



As it happens, the two processes above described 

 have come to be known as the British and American 

 processes respectively, because the British crushers 

 jiave only had the opportunity of handling the Egyp- 

 tian and Indian cotton-seed products in large quanti- 

 ties. The bulk of the American crop has, naturally, 

 always been handled in the States. The Indian crop 

 known as Bombay seed has always been imported 

 into this country and crushed whole without previous 

 delinting, because its seed-lint was scarcely long 

 enough to be worth removing, and its presence 

 in the cake (though it took long to convince the users 

 of it that this was true) did no material harm if 

 properly handled, while it gave a much bulkier, and 

 therefore cheaper, cake. 



The two improvements with which Mr. de Segundo 

 ^as been connected are, first, the production of a 

 .machine which, after ginning and delinting in the 

 ordinary way, takes a further quantity of "seed-lint" 

 from the seed. This seed-lint is of considerable com- 

 mercial value for many non-textile purposes, such as 

 paper-making, artificial silk, explosives, and cellulose 

 acetate, the peculiarity of the process being the very 

 clean and pure condition in which it delivers the 

 lint. Its removal also adds to the value of the seed 

 for crushing purposes, saves freight by reducing its 

 bulk, and minimises the danger of heating, and hence 

 the risk of fire by spontaneous combustion. The second 

 improvement is a process of removing the last vestige 

 of fibre from the hulls after decortication, thus taking 

 two further by-products out of the last residue of the 

 former process. It was the first of these improve- 

 ments that was mainly dealt with in the lecture. 



The importance of these processes to the cotton 

 industry is certain to be very considerable. There 

 are many new areas in the British Empire where 

 cotton is being developed, such as Uganda, Nigeria, 

 and parts of the Sudan, where the woolly seeded 

 varieties have been found the most suitable, but the 

 seed has never been fully utilised because the crops 

 were comparatively small, and the cost of handling 



