NATURE 



[May 29, 19 1 3 



p. 416, to show that a mixture of Ferndale dust and 

 air is probably explosive, but the Ferndale dust men- 

 tioned in my papers and book is from the anthracite 

 seams, and it is generally admitted now that anthra- 

 cite dusts and air are not explosive when unmixed 

 with firedamp. 



I think readers of Nature will agree that it 

 is not permissible to quote half a paragraph when the 

 rest of it amplifies. John Harder. 



Chemical Laboratory, Liverpool University. 



We take exception to Dr. Harger's statements, in 

 the quotation which he gives from p. 78 of his book, 

 that "dust explosions" such as Altofts "always pro- 

 ceed against the current of air," and that, "as a 

 rule, the branch of an ignition which travels with 

 the air-current fails to develop violence." 



The explosion at Altofts travelled to a distance of 

 more than a mile in No. 1 chain road in the same 

 direction as the air current had been previouslv 

 travelling, and produced a greater amount of wreck- 

 age in that heading than in any other part of the 

 mine. It did not reach the faces at any point, nor 

 did it enter the return airw'avs, for the reasons plainly 

 set forth in Proc. Roy. Soc, vol. xlii., p. 174. 



In our experience explosions are invariably found 

 to have penetrated into the faces wherever there has 

 been an uninterrupted train of coal-dust leading to 

 them; and they have, as a rule, failed to pass through 

 the return airways where the latter have not been 

 recently used as haulage roads, and where, conse- 

 quently, the coal-dust has become mixed with a large 

 proportion of shale dust. For instance, the composi- 

 tion of a samole of dust taken from the return air- 

 wavs at Altofts CoHiery after the explosion was as 

 follows : — 



Moisture 



Volatile matter other 

 Carbon (estimated) 

 Ash 



than moisture 



440 



10-37 



&9S9 



The experiments since made, both at Altofts and 

 Lievin. have shown that dust of this quality is 

 incapable of propagating an explosion. 



The reference to Proc. Roy. Soc, vol. xxviii., 

 p. 416, in the review, was not intended to show that 

 a mixture of Ferndale dust and air "is probably 

 explosive." as Dr. Harger suggests, but that return 

 air does not contain too little oxygen or too much 

 carbon dioxide to prevent its ignition when mixed 

 with coal-dust even of the same quality as that of 

 Ferndale. There are no anthracite seams in Fern- 

 dale Colliery ; all the seams consist of steam coal 

 of high-class quality. The Reviewer. 



Error in the Smithsonian Physical Tables. 



I HAVE just discovered a very awkward error in 

 Table 47, p. 35, of this valuable publication. The 

 table is headed " Least Squares," and gives the values 

 of the probability integral. To illustrate the error, an 

 example will be best. 



For argument 0-53, the table gives 055494, but this 

 is really the value for the argument 054, and the 

 same error runs throughout the table. An easy w-ay 

 to correct it is to increase by o-oi each of the figures 

 in the horizontal line heading the table. 



My copy is dated 1896, and I do not know if the 

 mistake has been set right since. 



I am reminded that some years ago I wrote to 

 Nature to suggest that all discovered errors in tables 

 should be sent to some official scientific body, which 

 should annually publish corrections of them. 



C. T. Whitmell. 



Hyde Park, Leeds, May 22. 



NO. 2274, VOL. 91] 



ANTHROPOLOGY IX WEST AFRICA. 1 



WE welcome a report by Mr. N. W. Thomas 

 on the people of the Awka district, Ibo 

 country, Southern Nigeria. Mr. Thomas is the 

 Government anthropologist and has already given 

 us an interesting report on the Edo-speaking 

 people. 



The present report is divided into three parts ; 

 the first treats of the law and customs of the 

 people, the second is a dictionary, and the third 

 contains proverbs, narratives, and vocabularies. 



The most interesting to the general reader is 

 undoubtedly part i. In chapter ii. Mr. Thomas 

 gives some most interesting demographic facts 

 and figures. Referring to infanticide, he says : — 



In addition to this legal infanticide (the exposure 

 of twins) ... I have more than once heard that the 

 first-born of every woman is killed; my informants 

 were Roman Catholic missionaries, who certainly 

 know the native and his ways, and my own statistics 

 seem to bear out the statement. 



This is very interesting, and bears out the principle 

 common, evidently, to most West Africans, that 

 the first-born belongs to the owner of the family 

 (i.e. the dead father). He, as head of the family, 

 is worshipped by his son, grandson, great-grand- 

 son, and great-great-grandson. He (the dead one) 

 has need of followers in dead man's land, and 

 claims this toll in exactly the same way as the 

 owner of a goat will claim its first-born from the 

 farmer who is looking after it for him. 



The genealogical tables are of great interest, 

 and, in spite of the fact that the number of wives 

 to one husband varies from four to eight, "the 

 proportion of boys to girls in the births was fifteen 

 to eleven." But there are more grown-up females 

 than males. Taking the statistics for living 

 males and females among" the Ibo (12 18 males to 

 1340 females), we can only conclude that the 

 mortality among boys is greater than among 

 girls or that this majority is largely com- 

 posed of widows. That husbands in such a 

 country should have four to eight wives must 

 deprive a great number of men of the luxury of 

 a wife. Many chiefs tacitly acknowledge this 

 want and have appointed females in each town or 

 village to supply the need. But in spite of this 

 precaution young bachelors are constantly com- 

 mitting adultery. Men with one wife in this 

 district account for 760 male and 787 female 

 children, men with four wives for 137 male and 

 113 females. This chapter is most instructive to 

 those who are interested in the question of poly- 

 gamy versus monogamy. 



Chapter iii. is entitled "Religion," and, written 

 by such a master of anthropology- as Mr. Thomas, 

 is a lesson to all students of religion in Africa. 

 Those of our readers who have followed the 

 development of this great colony will not have 

 forgotten the suppression of the so-called juju at 



1 " Anthropological Report on the Ibo-spealting Peoples of Nigeria." By 

 N. W. Thomas Part i.. Law and Customs of the Ibo of the Awka Neigh- 

 bourhood, S. Nigeria. Pp. i6t+xx plates. Part ii., English-Ibo and 

 [bo-English Dictionary. Pp. vii + - QI . Part iii.. Proverbs, Nartatives, 

 Vocabularies, and Gtammar. Pp. vi + 109. (Lond. n : Harrison and Sons, 

 1913-) 



