472 



NATURE 



\Sept. 1 6, 1880 



the time of this observation from oh. 43m. to oh. 8m. p.m. was 

 discussed, and it was resolved to accede to the proposal, notwith- 

 standing the inconvenience whicli the change might entail in 

 individual systems of observation. 



The Proposal for Concerted Arctic Observations, — The Inter- 

 national Polar Commission appointed at Hamburg, in October, 

 1S79, presented a report of a meeting it had recently held at 

 Berne, and announced that Count Wilczek and Lieut. Wey- 

 precht had consented to postpone their expedition to Nova Zembla 

 until 18S2 in order to allow of more time for the organisation of 

 the other expeditions destined to co-operate with them. The 

 International Committee resolved to aid the scheme by all the 

 means in their power. 



The Publication of Data refo'ring to Pain, &'c. — A proposal 

 made by Dr. Koppen for an improved method of publication of 

 information relating to rain, snow, &c., was ordered to be circu- 

 lated among the diflerent observatories, in order to obtain 

 opinions as to its suitability. 



Telegraphic Communication with the Atlantic Islands.— Cs-ft 

 Hoffmeyer submitted a resolution as to the desirability of 

 laying cables to the Faroes, Iceland, Greenland, and to the 

 Azores. The Committee expressed their hope that it might be 

 found possible to lay these caljles, which would be of very great 

 importance for the weather service of Europe. 



The Piiblicaeion of Average Values for Meteorological Data. — 

 The Committee, at Capt. Hofifmeyer's suggestion, recommended 

 that all meteorological organisations should publish regularly the 

 mean values for the most important elements for the telegraphic 

 and international stations. 



The Catalogue of Meteorological Literature. — A proposal made 

 by Dr. Hellmann of Berlin for the preparation of such a cata- 

 logue was considered. Dr. Hellmann stated that he had calcu- 

 lated the cost of preparation of the catalogue of printed boo'-;s 

 and memoirs at about 550/., and that of printing and publication 

 (1,000 copies) at about 750/. 



Several of the memliers of the Committee promised to aid in 

 canning out the scheme, if it were seriously undertaken, by 

 the preparation of catalogues of the literature which exists in 

 their own individual languages. The subject was finally referred 

 to Mr. Scott and Dr. Hellmann, with power to act if they 

 found sufficient encouragement. 



As to the catalogue of unpublished records of observations, 

 no definite resolution was adopted. 



International Tables for the Reduction of Observations. — It 

 was stated that a publishing firm in Leipzig was prepared to 

 print and publish such tables at its own risk if the "copy" 

 were delivered to them. The subject was referred to Prof. 

 Mascart and Prof. Wild for the preparation of a definite plan for 

 the calculation of the tables. 



The Committee will include in its Report, which will shortly 

 appear, a notice of the progress made in each country in carrying 

 out the resolutions of the Congress of Rome. 



It only remains to say that the members of the Committee 

 were most hospitably entertained by the Federal Council and by 

 the Municipality of Berne. 



AGRICULTURAL CHEMISTRY^ 

 C OME of my predecessors in this chair, whose duties as teachers 

 '-^ of chemistry lead them to traverse a wide range of the subject 

 every year, have appropriately and usefully presented to the 

 Section a rhume of the then recent progress in the manifold 

 branches of the science which have now such far-reaching rami- 

 fications. Some, on the other hand, have confined attention to 

 some department with which their own inquiries _havejmore 

 specially connected them. 



But it seems to me that there is a special reason why I should 

 bring the subject of Agricultural Chemistry before you on the 

 present occasion. Not only is the application of chemistry to 

 agriculture included in the title of this Section, but in 1837 the 

 Committee of the Section requested the late Baron Liebig to 

 prepare a report upon the then condition of Organic ChemistiT, 

 and it is now exactly forty years since Liebig presented to the 

 British Association the first part of his report, which was entitled 

 "Organic Chemistry in its Applications to Agriculture and 

 Physiology " ; and the second part was presented two years later, 

 in 1842, under thetitle of "Animal Chemistry, orOrganicChemistry 



' ppeaing Address in Section B (Chemical Science), at the Swansea 

 meeting of the British Association, by J. H. Gilbert, Ph.D., F.R.S., 

 V.B.Ub., F.L.S., President of the Section. 



in its Application to Physiology and Pathology." Yet, so far as I 

 am aware, no President of the Section has, from that time to the 

 present, taken as the subject of his address the Application of 

 Chemistry to Agriculture. 



Appropriate as, for these reasons, it would seem that I, who- 

 have devoted a very large portion of the interval since the publi- 

 cation of Liebig's works, above referred to, to agricultural 

 inquiries, should occupy the short time that can be devoted to 

 such a purpose in attempting to note progress on that important 

 subject, it will be readily understood that it would be quite im- 

 possible to condense into the limits of an hour's discourse any- 

 thing approaching to an adequate account, either of the progress 

 made during the last forty years, or of the existing condition of 

 agricultural chemistry. 



For what is agricultural chemistry? It is the chemistry of the 

 atmosphere, the chemistry of the soil, the chemistry of vegeta- 

 tion, and the chemistry of animal life and growth. And but 

 a very imperfect indication of the amount of labour which has 

 been devoted of recent years to the investigation of these various 

 branches of what might at first sight seem a limited subject will 

 suffice to convince you how hopeless a task it would be to seek 

 to do more than direct attention to a few points of special 

 interest. 



From what we now know of the composition and of the 

 sources of the constituents of plants, it is obvious that a know- 

 ledge of the composition of the atmosphere and of water was 

 essential to any true conception of the main features of the vege- 

 tative process; and it is of interest to observe that it was almost 

 simultaneously with the establishment, towards the end of 

 the last century, of definite knowledge as to the composition of 

 the air and of water, that their mutual relations with vegetation 

 were first pointed out. To the collective labours of Black, 

 Scheele, Priestly, Lavoisier, Cavendish, and Watt, we owe the 

 knowledge that common air consists chiefly of nitrogen and oxy- 

 gen, with a little carbonic acid'; that carbonic acid is composed 

 of carbon and oxygen ; and that water is composed of hydrogen 

 and oxygen ; whilst Priestly and Ingenhousz, Semiebiei; and 

 Woodhouse, investigated the mutual relations of these bodies 

 and vegetable growth. Priestly observed that plants possessed 

 the faculty of purifying air vitiated 'by combustion or by the 

 respiration of animals ; and, he having discovered oxygen, it was 

 found that the gaseous bubbles which Bonnet had shown to be 

 emitted from the surface of leaves plunged in water consisted 

 principally of that gas. Ingenhou;z demonstrated that the action 

 of light was essential to the development of these phenomena ; 

 and Sennebier proved that the oxygen emitted resulted from the 

 decomposition of the carbonic acid taken up. 



De Saussure concluded that air and water contributed a much 

 larger proportion of the dry substance of plants than did the soils in 

 which they grew. In his view a fertile soil was one which yielded 

 liberally to the plant nitrogenous compounds, and the incom- 

 bustible or mineral constituents ; whilst the carbon, hydrogen, 

 and oxygen, of which the greater proportion of the dry substance 

 of the plant was made up, were at least mainly derived from the 

 air and water. 



Perhaps I ought not to omit to mention here that,each year for ten 

 successive years, from 1802 to 1812, Sir Humphry DavyJdelivered 

 a course of lectures on the "Elements of Agricultural Che- 

 mistry," which were first published in 1813, were finally revised 

 by the author for the fourth edition in 1S27, but have gone 

 through several editions since. In those lectures Sir Humphry 

 Davy passed in review and correlated the then existing know- 

 ledge, both practical and scientific, bearing upon agriculture. 

 He treated of the influences of heat and light ; of the organisa- 

 tion of plants ; of the difference, and the change, in the chemical 

 composition of their different parts ; of the sources, composition, 

 and treatment of soils ; of the composition of the atmosphere, 

 and its influence on vegetation ; of the composition and the 

 action of manures ; of fermentation and putrefaction ; and finally 

 of the principles involved in various recognised agricultural 

 praltices. 



With the exception of these discourses of Sir Humphry Davy, 

 the subject seems to have received comparatively little attention, 

 nor was any important addition made to our knowledge in regard 

 to it during the period of about thirty years from the date of the 

 appearance of De .Saussure's work in 1S04 to that of the com- 

 mencement of Boussingault's investigations. 



In 1S37 Boussingault published papers on the amount of 

 gluten in different kinds of wheat, on the influence of the clearing 

 of forests on the diminution of the flow of rivers, and on the 



