594 REPORY1—1905. 
whole agricultural charactet of the field is changed : the soil works so 
heayily that it is difficult to keep the land under the plough ; and as 
grass land it carries a very different and altogether inferior class of 
vegetation. On the experimental fields it has been possible to measure 
the rate at which natural agencies, chiefly the carbonic acid and water in 
the soil, are temoving the calcium carbonate that has been introduced 
into the surface soil, and it is found to be disappearing from the unmanured 
plots under arable cultivation at an approximate rate of 1,000 lb. per 
acre per annum; arate which is increased by the use of manures like 
sulphate of ammonia, but diminished by the use of nitrate of soda and of 
dung. Failing the renewal of the custom of chalking or liming—and its 
disuse is now very general—the continuous removal of calcium carbonate 
thus indicated must eventually result in the deterioration: of the land to 
the level of that which has never been chalked at all, and even a state of 
sterility will ensue if much use is made of acid artificial manures. That 
many soils containing naturally only a trace of calcium carbonate remain 
fairly fertile under ordinary farming conditions is due on the one hand to 
an action of the plant itself, which restores to the soil a large proportion 
of the bases of the neutral salts upon which it feeds, and partly to the 
action of certain bacteria in the soil, which ferment organic salts like 
calcium oxalate existing in plant residues down to the state of carbonate. 
Were it not for these two agencies restoring bases the soil must naturaily 
lose its neutral reaction, since the process of nitrification is continuously 
withdrawing some base to combine with the nitric and nitrous acids it 
sets free. 
This varying distribution of calcium carbonate in soils suggests 
another section of my subject, in which great activity has prevailed of 
late—the undertaking of a systematic series of soil analyses in any dis- 
trict, with a view to making soil maps that shall be of service to the 
agriculturist. The Prussian Government have long been executing such 
a soil survey, and during the last few years a similar project has been 
pushed forward with great energy in the United States; in France and 
in Belgium several surveys are in progress, but in the United Kingdom 
the matter has so far_only excited one or two local attempts. While the 
basis of such work must always be the geological survey of the district, 
a geological survey in which, however, the thin ‘drift’ formations are of 
greater importance than the solid geology, there are certain other items 
of information required by the farmer which would have to be supplied 
by the agricultural specialist. In the first place the farmer wants to be 
told the thickness of the superficial deposits : he requires frequent ‘ ground 
profiles,’ so that he can construct an imaginary section through the upper 
10 feet or so of his ground. To take a concrete example: the chalk in 
the South of England is very often overlaid by deposits of loam, approach- 
ing the nature of brick earth, and the agricultural character of -the land, 
its suitability for some of the special crops, like hops and fruit, which 
characterise that district, will be wholly different according as the deposit 
is 3 feet or 10 feet deep. The proximity and, if near the surface, the 
direction of flow of the ground water are also matters on which there 
could be given to the farmer information of great importance when 
questions of drainage or water supply have to be considered. It is 
necessary also to refine upon the rough classification of the soil and sub- 
soil which alone is possible to the field surveyor, one of whose functions 
will be to procure typical samples of which the texture and physical 
ici 
OR th i 
