228 



NATURE 



[May II,. 1916. 



special endeavours have been made to replace expen- 

 sive articles of diet by less costly substitutes, the. 

 normal food has been at once supplied in those cases 

 where the health of the animals appeared to suffer. 



Experiments on the action of tobacco decoctions in 

 destroying certain insect pests of the vine are described 

 by Dr. Mario Topi in the Aiii dei Lincei, xxv., (i), 5. 

 Two varieties of grape vine were selected, and it was 

 found that with two applications of the decoction the 

 larvae of Eudemis were about half as numerous on 

 the treated plants as on the others, and those of 

 Conchylis were slightly lower too. On the other hand, 

 the number of damaged branches was also reduced 

 by about 50 per cent, by the treatment. 



The heavy loss of nitrate by washing out from 

 arable soil during the wet winter of 19 15-16 is very 

 clearly shown by Dr. E. J. Russell and Mr. A. Apple- 

 yard in the current number of the journal of the 

 Board of Agriculture. The most striking case is that 

 of the Broadbalk dunged plots at Rothamsted, one of 

 which was fallowed and the other cropped. During 

 the summer the fallow plot accumulated nitrate until, 

 by the middle of September, the top 18 in. of soil 

 contained 170 lb. of nitric nitrogen per acre, equiva- 

 lent to nearly 10 cwt. of nitrate of soda. The losses 

 then began, and were so heavy in November and 

 December that by February the magnificent stock of 

 nitrate had been reduced to 50 lb. of nitrogen. This 

 loss is equivalent to 7 cwt. of nitrate of soda, no 

 small item at present prices. The Broadbalk fallow 

 plot is no doubt an extreme case, but the cropped plot 

 also suffered considerable loss. If never accumulated 

 nitrate like the fallow plot, the maximum being 90 lb. 

 of nitrogen per acre; half of this was lost during 

 the winter, or as much nitrogen as is contained in 

 24 bushels of wheat and the corresponding amount of 

 straw. The losses are naturally greatest on these 

 heavily manured soils, but the fields which were not 

 unusually well done lost about 30 lb. of nitrogen per 

 acre. Some of the loss on the fallow plot could have 

 been prevented by sowing mustard or other quick- 

 growing crop in September. This could have been 

 fed off or ploughed in, thus holding the nitrogen in 

 less soluble form until the spring. The obvious lesson 

 is that land which has been got into good condition in 

 autumn should at once be sown with either the crop 

 it is intended to carry or a catch crop. 



The Summary Report of the Mines Branch of the 

 Department of Mines for 1914 has just been issued 

 by the Canadian Government. This gives a brief 

 rdsumd of the work done by this branch during the 

 year in question, together with a preliminary report 

 on the mineral production of the Dominion. It ap- 

 pears that there is a falling off in the output of nearly 

 all mineral products and metals, the only exceptions 

 of any importance being in the two items of pyrites 

 and natural gas ; in the former the increase amounts 

 to 42 per cent., in the latter to only 3 per cent. The 

 total value of the mineral production is given as 

 128,475,499 dollars, as against 145,634,812 dollars in 

 19 13. The decrease is stated to be due to conditions 

 arising from the war, owing to which many mines 

 have either closed down or decreased their activities. 

 It is not to be inferred that the diminution is due to 

 any other than temporary causes. 



The Geological Survey of Great Britain has issued 

 a memoir (price 45. 6d.) on "The Thicknesses of 

 Strata in the Counties of England and Wales, exclu- 

 sive of Rocks Older than the Permian." The direc- 

 tor. Dr. Strahan, has taken a large share in the 



. NO. 2428, VOL. 97] 



preparation of this useful work of reference, .which- 

 will aid teachers in drawing up correct geological, 

 sections, and will serve as a permanent guide to those, 

 who seek for water or for coal. Sketch-maps are 

 given of each county, showing the sites where sub- 

 terranean information has, been obtained, and in some 

 cases contour-lines are drawn to mark the depths 

 below sea-level at which certain important horizons 

 may be struck. The base of the Permian (or top of 

 the Coal Measures) is thus included in the features 

 shown in Nottinghamshire. The lowering of the 

 denuded chalk surface below sea-level and the infilling 

 of its hollows by Glacial deposits are well seen in the 

 map of Norfolk, where the Saham Toney boring 

 passed through 248 ft. of Glacial drift, the base of 

 which lies more than 100 ft. below the sea. Under 

 the head of Kent, we note that the Dover boring has 

 penetrated 1152 ft. of Coal Measures. The depths at 

 which coal-bearing strata have been reached in other 

 counties, such as Cheshire and Leicestershire, will be 

 looked on with interest by economists. 



The United States Coast and Geodetic Survey 

 has issued a tabulated list of the geographical posi- 

 tions on the North American Datum, with descrip- 

 tions and elevations of all triangulation stations on 

 the coast and geodetic survey in Alabama, on the 

 Gulf Coast in Mississippi, and on the eastern oblique 

 arc in Louisiana (Special Publication, No. 24). The 

 field work of the triangulation included in this pub- 

 lication was done between the years 1846 and 191 1, 

 and many of the original stations could not be 

 recovered, but where possible stations were re- 

 marked. The results of the entire eastern oblique 

 arc triangulation appeared in a previous publication 

 in 190 1 (Special Publication, No. 7). That publica- 

 tion, however, dealt primarily with the purely 

 scientific problem of the determination of the figure 

 of the earth, and only the positions of those points 

 included in the main scheme of triangulation were 

 published. 



Prof. Hilderbrandsson {Kungl. Svenska Veten- 

 skapsakademines Handlingar, Band 51, No. 8) gives 

 some further results of his researches. He states that 

 in winter the course of the meteorological elements 

 over the part of the ocean lying between Iceland and 

 Norway agrees with that which occurs over the north 

 of Europe, but is in opposition to the course of the 

 same elements over the subtropical region, the Azores 

 to the Mediterranean. The same opposition between 

 north and south is said to occur in North America, 

 but inversely to the relation in Europe, so that if the 

 v.'inter is cold in the north of Europe, it is cold in 

 Mexico and the United States, but mild in the south 

 of Europe and in the north of North America. Vari- 

 ous other relationships are given, and are supported by 

 tables and charts. If the correlation coefficients were 

 worked out they would not be very high, but Prof. 

 Hilderbrandsson states that the relations are disturbed 

 by external causes of a superior order, such as the 

 varying heat of the sun. 



Some observations on the green ray sometimes ob- 

 served at sunrise and sunset are described by G. 

 Guglielmo in the Atti dei Lincei, xxv., (i), 5. The 

 author discusses the various theories that have been 

 advanced to account for the fact that the duration of 

 the phenomenon may exceed the limit attributable to 

 dispersion. He finds, moreover, that the ray is some- 

 times more bluish and sometimes less so. Among the 

 various causes which may modify the effect or its 

 duration are mentioned atmospheric absorption of the 

 violet and indigo rays, waves in the atmosphere, and 

 abnormal variations of density in the lower strata. 



