34 



NATURE 



[March 8, 191 7 



operatian between the technical faculties of our univer- 

 sities and the "industries concerned, in America such 

 cooperation is already an established fact, and reports 

 such as the present one show evidence of its value. 



This bulletin is merely a preliminary one, present- 

 ing a complete and concise account of what is known 

 up to the present on the subject of subsidences due 

 to mining operations, and the authors have done 

 their work in a most thorough and painstaking 

 fashion, and have missed very li'ttle of the published 

 information on the subject, in spite of the difficulty 

 of bringing it together from the large number of 

 scattered records through which it is disseminated. 

 It need scarcely be said that the subject is one of the 

 greatest importance in this country, where so many of 

 our most densely populated industrial centres are 

 situated upon the coalfields themselves. The problem 

 whether large masses of coal should be left in the 

 form of supporting pillars, and thus be permanently 

 lost to the nation, or to what extent it is advisable 

 to remove them, with the risk, or even with the cer- 

 tainty, of causing a certain amount of surface damage, 

 is obviously one of first-rate imjwrtance, especially at 

 times like the present, when the proper conservation 

 and full utilisation of our natural resources demand 

 our utmost attention. 



Messrs. Young and Stock have contented them- 

 selves with summarising the theories on subsidence 

 -[iromulgated by various writers, notably the Belgian, 

 French, Prussian, and Austrian theories ; there cannot 

 really be said to be any British or American theories, 

 althoug^h various British engineers have proposed 

 formulas, notablv for determining the angle of "draw," 

 and the size of the coal pillars that must be left 

 in order adequately to protect any given area of sur- 

 face; the wide divergence of these various formulas 

 is well shown by a diagram, reproduced from a paper 

 by Prof. George Knox, which shows that some of 

 these give results ten times as great as those given 

 t)y others. 



The introductory notice to the present bulletin sug- 

 gests that the Illinois authorities propose to study the 

 problem in a systematic fashion, by taking careful 

 levels across selected groups of mines at regular in- 

 tervals, and simultaneously noting the conditions of 

 the underground workings, such observations to be 

 continued for a number of years, when it may be 

 hoped that it will be found possible to correlate sur- 

 face subsidences and underground workings, and thus 

 to obtain data that will enable the conditions of 

 maximum economv to be determined. This is a sub- 

 ject that might with the greatest advantage be taken 

 up on similar lines bv one or other of the committees 

 formed to deal with industrial research in this 

 •country. H. L. 



FURTHER STUDIES IN PLANT GENETICS. 

 'T*HE September number of the American Naturalist 

 ^ (vol. 1., No. 597) is devoted to studies of inherit- 

 ance in plants. Dr. H. H. Bartlett writes on "The 

 Status of the Mutation Theory, with especial reference 

 to CEnothera." He "finds incredible the arguments 

 that have been brought forward in favour of the idea 

 that mutation and Mendelian segregation are the 

 same." Nevertheless, it still remains to be decided 

 "whether or not mutation is always, or ever, condi- 

 tioned by previous hybridisation." 'Dr. O. E. White 

 describes some researches in continuation of Mendel's 

 original subject— the inheritance of cotvledon colour 

 in Pisum. Alleged differences betv\een "the colour of 

 segregated seeds of the F, generation and those of the 

 original parents are attributed to environmental 

 V changes : yellow-cotyledon varieties may produce green 

 NO. 2471, VOL. 99] 



seeds because of immaturity, absence of sunlight, or 

 excess of moisture, while green-cotyledon varieties may 

 fade to yellow or yellowish-green through excess of 

 sunlight. In one variety — " Goldkonig " — with yellow 

 cotyledons, the yellow colour is, contrary to the usual 

 rule, recessive to green. This form "may be regarded 

 as lacking both the factor for causing green pigment 

 and the factor for causing that pigment to fade on the 

 maturity of the seed." When "Goldkonig" is crossed 

 with j'ellow-seeded varieties in which yellowness is 

 dominant, the F, generation are all yellow-seeded, and 

 the F2 generation are segregated in the proportion of 

 three green to thirteen (9 + 3+1) yellow. 



"Inheritance of Sex in the Grape" is discussed by 

 W. D. Valleau. Wild vines bear flowers which are 

 functionally either male or female, but the carpels or 

 pistils are respectively present in a reduced condition ; 

 the plants are thus transitional between the herm- 

 aphrodite and the dioecious form. Functional herm- 

 aphrodites, however, appear in cultivation. Breeding 

 experiments suggest that "both the staminate and 

 functionally pistillate vines carry the determiners for 

 femaleness and maleness, respectively, partially sup- 

 pressed." 



The Journal of Genetics ior September (vol. vi.. 

 No. i) is completely occupied by Prof. A. H. Trow's 

 analysis of form and inheritance in the common 

 groundsel {Senecio vulgaris). In a long paper he dis- 

 cusses the number of nodes and their distribution along 

 the main axis in this species and its segregates. 

 Dividing the families of plants studied into " low " 

 (9-16 nodes), "medium" (18-26 nodes), and "high" 

 (30-31 nodes), he finds that medium characters arc 

 dominant to both low and high, and infers, therefore, 

 the existence of two pairs of alternative determinants. 

 However, from the cross "medium" x "high" there 

 emerge families with from 36-39 nodes, forming a 

 "very high" group; this "segregates out from 'high " 

 as a recessive." From the cross "low" x "high"' 

 other anomalous results were obtained, and the author 

 foresees many years' work before definite conclusions 

 can be reached. In a short paper Prof. Trow dis- 

 cusses the inheritance of "albinism" in groundsel; 

 he finds that in some forms the expected ratio of green 

 to white plants as 15 to i is obtained in the F2 genera- 

 tion ; in others it is unaccountably departed from. 



THE ORGANISATION AND DEVELOPMENT 

 OF CHEMICAL INDUSTRY AND RE- 

 SE.ARCH.' 

 COUTH AFRICA is a country which has hitherto 

 *^ existed, and still does at the present moment 

 exist, on its rich stock of raw materials. Its exports, 

 in addition to the raw products of agriculture, are 

 chiefly metals, crude and unrefined, and diamonds 

 uncut. The chief chemical industry is the prepara- 

 tion of raw gold bullion from the quartzitic ore of 

 the Transvaal. This is carried out in three operations 

 — the first being fine pulverisation by mechanical 

 means ; the second, amalgamation with mercury ; 

 and the third, solution of the unamalgamated gold 

 still remaining by means of sodium ,cyanide solution, 

 followed by reprecipitation with excess of zinc shav- 

 ings and final treatment of the metal, so as to gfet 

 rid of as much of the base metal present as possible 

 before pouring into commercial bars. The major 

 portion of the plant necessary for these operations 

 consists of iron and steel, and the raw materials for 

 their manufacture exist in comparative abundance in 

 the Transvaal. A thorough and scientific'lly com- 



1 From the presidential address delivered to Section B — Chemistry, 

 neology. Metallurgy, Mineraloey, and Geography — of the South African 

 Association for the Advancement of Science at the Maritzburg meeting, 

 July 4, 1916, by Prof. J. A. Wilkinson. 



