458 



NATURE 



\Oct. 8, 1874 



meteorologists, in previous years the immense majority of 

 British storms have had their centres to the northward of 

 the British Isles. The proximate cause of the peculiar 

 distribution of storms of wind during 1873 lay not in the 

 position of the paths of the storm-centres, Init in the manner 

 of the distribution over Great Britain of the steeper baro- 

 metric gradients of the atmospheric depressions of the 

 storms of 1873 as they swept eastwards over north- 

 western Europe. 



It would have been satisfactory if the comparison 

 which has been instituted by the Office between the ob- 

 servations from Valencia, in Ireland, and Angra do Hero- 

 ismo, in the Azores, had been detailed in the Report, 

 seeing that it is inferred from the result, " beyond the pos- 

 sibility of a doubt, that reports from a station situated at 

 the Azores would be practically useless to the Office in 

 giving early intimation of approaching storms." The 

 grounds of this strongly-expressed opinion on a point of 

 some importance in weather telegraphy, and contrary to 

 the views entertained by not a few meteorologists, ought 

 to have been stated. 



In the Committee's Quarterly Weather Report for 

 1870 the position of the thermometers at each of 

 their seven observatories was described and figured. 

 We hope that in the next Report a detailed account 

 will be given of the position and exposure of the ther- 

 mometers at the stations from which the daily tele- 

 graphic weather reports are sent, in order that meteorolo- 

 gists may judge how far the observations made at these 

 stations might be available in investigating the climate of 

 the British Isles, and in some other meteorological in- 

 quiries. This is by many deemed necessary, especially 

 when it is considered that the Office has not hitherto pub- 

 lished any mean temperatures from the daily observations 

 made at their telegraphic stations, and some of these 

 stations, particularly in Ireland, are in parts of the British 

 Isles, of whose climate little is yet known. 



GEOLOGY AND AGRICULTURE 



Applications dc Giologie ct rAgriculture, par M. Am^dde 

 Burat, Engineer, Professor at the Central School of 

 Arts and Manufactures. (Paris: Rothschild, 1S74,) 



C'EOLOGYis one of the most ^interesting of modern 

 t sciences. Soon after it assumed shape high hopes 

 were entertained as to its value to the farmer : up to the 

 present these hopes have not been realised. And yet the 

 study of geology is most intimately connected with 

 agricultural pursuits. Surface geology deals with the soil 

 which daily occupies the thoughts and labours of the 

 farmer. There is one phase of surface geology which has 

 been almost wholly neglected of late ; we refer to the con- 

 nection between soils and the rock-formations from which 

 soils have been derived. It is here possibly that there is 

 the widest field for original research. It was hoped that 

 this branch of agricultural science would have received 

 much attention from the present secretary to the Royal 

 Agricultural Society of England, who had previously been 

 a diligent student of geology and secretary to the Geo- 

 logical Society. .So far, his hands would appear to have 

 been full of other work, and he has done little where 

 much was expected. 



That there is a most intimate connection between soils 

 and rock-formations is well known. In some places the 

 soil is the direct product of the disintegration of the 

 underlying rock. It more frequently happens, however, 

 that the soil has not been derived from the rock on which 

 it rests, but consists of drifted material. The study of 

 this drifted material is most interesting to the geologist, 

 and ought to be most instructive to the farmer. It enables 

 the geologist to understand the direction and force of 

 former water-currents ; and thus throws light on obscure 

 phenomena. A careful examination of the drift enables 

 us to trace the origin of the soil. Thus, for example, a 

 study of the'stones and pebbly particles of the soil, enables 

 us not only to know the rocks from which it was derived, 

 at all events partly, but also to understand the rate at 

 which plant- food may become liberated on the soil by the 

 disintegration of these very stones and pebbles. On this 

 point a word of explanation may be here offered. 



If we examine a fertile soil at any time we shall find 

 that only a very small portion of its substance (seldom 

 more than one per cent.) is in a condition fit for nourish- 

 ing our crops, the great bulk of its substance being locked 

 up in a condition at the moment unavailable. By the 

 action of air, of moisture, of heat, and of manurei 

 part of this unavailable matter becomes available for 

 crops. It is on the rate at which the process of disinte- 

 gration — -or liberation of plant-food — takes placa that 

 the natural power of production of the soil chiefly 

 depends. The study of agricultural geology from this 

 point of view is manifestly of the highest scientific and 

 practical importance : it opens up a wide field for original 

 research. We had hoped, on receiving M. Burat's little 

 volume, that he would have taken up the subject. We 

 have been disappointed. 



The work is, not, however, without merit. The language 

 is simple, and the style as lucid as need be. 



In the introduction the author leads the reader to ex- 

 pect a fuller exposition of the relation between geology 

 and practical farming than he will find in the volume. 

 The book contains four chapters. The first is a disquisi- 

 tion, couched in very general terms, on the physical cha- 

 racters and composition of soils. As an illustration of 

 the very general character of the matter we quote the 

 average composition of fertile soils (p. S) : — 



Every 100 parts contain — 



35 gravelly particles of the size of peas 

 45 ditto ditto millets 



10 ditto of fine sand 



10 ditto of fine material, separable 



by washing. 



We are next furnished with a general "ultimate" 

 chemical composition of an average soil. Information 

 of this kind possesses no value except to the junior 

 student. 



The second chapter is devoted to manures, which are 

 treated in a popular manner. The third chapter is on the 

 action of water, and the subject is treated in an interesting 

 manner ; the services of the Abbe Paramere are duly ac- 

 knowledged. The fourth, and last, is the most interesting 

 chajjter in the work. Here the author shows very cle.irly 

 that there is a connection between geology and agricul- 

 ture, drawing illustrations from the primary, secondary, 

 and tertiary groups of rocks. Soils formed from granitic 



