NATURE 



[August io, 191 i 



great Zambezi gorge. Mr. Johnson, however, agrees 



ii. Codrington that these implement-bearing 



gravels are later than the gorge, and were washed to 



their present position from slightly higher ground. 





^J? 



in Surrey, and to a smaller extent in the suburban 

 districts of Kent, it is natural io find a large part of 

 the farm report taken up by the preliminary results- 

 of an inquiry into the cost of milk production. On 

 no aspect of farming have we le^> information than 

 on costs of production, and on none is more informa- 

 tion needed at the present time, when economies have 

 to be introduced at every turn. It will not astonish 

 anyone acquainted with farmers to learn thai 

 cost of food required to produce a gallon of milk 

 varied from 3'8d. to io'~,d. The usual variation was 

 from 5<2. to Sd., the average on fifty-nine farms being 

 6'6d. An inquiry of this nature is beset with many 

 difficulties and pitfalls, and it would be well for the 

 authors to obtain advice from an expert statistician 

 as to the methods to be employed and the interpreta- 

 tion of the results ; a more useful subject for investiga- 

 tion has rarely been attacked by dairy workers. 

 Mr. Theobald's report on economic zoology covers- 



130 pages, and is, as usual, well illustrated. 



Among new fruit-tree pests are noted the pale 

 .-:>^^K---^^^z-±^~^ii^%~. brindled beauty (Phigalia pikKsaria, Hb.) and 

 ,.gp---'---- A - ------------- ■---■'&■"•*' s\v the light emerald moth (Metrocampa mar- 



#'•'' garitaria, Linn.). Many of the old pests, 



still continue to baffle all the efforts of the grower, 

 such as the apple blossom weevil (Anthonomus 

 pomorum, Linn.) and the raspberry beetle (Bytariis 



.-■ft? 



*5fc- -■■')>?■ 



South Africa." 



They are of a considerable, though not of the 

 enormous antiquity, demanded by the other hypo- 

 thesis. 



The author adds many new examples of the rock 

 drawings to those issued in his previous works, in- 

 cluding some formed by pecking rock surfaces. Some 

 of these drawings he regards as made by men of the 

 Solutric period ; and, as the men of Solutr6, though 

 skilled artists, did not use the rock-pecking process, 

 Mr. Johnson concludes that the European and South 

 African makers of Solutric implements were derived 

 by separate migrations from a common eastern 

 ancestor. 



Mr. Johnson accepts the view that the Zimbabwe 

 was made by a Bantu people. He records (p. So) an 

 interesting tradition in the northern Transvaal of a 

 race of miners who were not Kaffirs, and whom he 

 suggests were Arabs ; but as these miners had guns 

 thev belonged to comparativelv modern times. 



J. W. G. 



THE ADVISORY WORK OF AN 

 AGRICULTURAL COLLEGE. 1 

 \\~HEN county councils make grants to agricul- 

 ' ' tural colleges they expect to get in return for 

 their money a certain amount of instruction for 

 students at the college and for farmers at market-day 

 lectures, and a good deal of advisory work for rate- 

 paying agriculturists. The volume before us repre- 

 sents the output of the Wye College staff in advisory 

 work during the year 19 10. 



In view of the great importance of milk production 



1 The Journal of the South-Eastem A5ricultur.il College, Wyf, Kent. 

 No. 10. I (London and Ashforcl : Headier Bros., iq.o.) Price 



7s- 6rf. (] Kern and Surr. \ |i. bd.) 



NO. 2l8o, VOL. 87] 



e March Moths. The lower 

 • of the Lackey moth (X 4). 



• in her eger-band 

 the Journal of the South- 



tomentosus, Fab.), but there is put forward for con- 

 sideration an interesting statement from " an old book" 

 to the effect that woolly aphis may be cured by planting 

 a nasturtium against the infested tree. But the tw 



