382 



NATURE 



[January 17, 191; 



it is true, as they remark, that compared with that 

 of many other industries the chemistry of the oils, 

 fats, and waxes is remarkable for its simplicity ; 

 but unless the reader has already had some 

 grounding- in organic chemistry he will probably 

 conclude, from the pages of formulae put before 

 him in the earlier part of the work, that it is not 

 such a very simple matter after all. 



This apart, the book is a serviceable one for the 

 purpose in view. Practical analytical work is left 

 to be expounded in a companion treatise : the pre- 

 sent volume explains the chemical processes and 

 terms used in connection with the fixed oils and 

 their congeners, and gives the physical and chemi- 

 cal data characterising the various products ; but 

 it is not intended to be a guide and counsellor for 

 the experimenter. For example, the meaning of 

 " viscosity " is shown, and the values of this con- 

 stant are given, but detailed directions for actu- 

 ally determining the viscosity are not included ; 

 presumably these are reserved for the companion 

 volume. 



The interpretation of analytical data, not the 

 way to obtain them, is the key-note of the book. 

 A large amount of information is given in a sys- 

 tematic manner and in a very handy form. The 

 diagrammatic representations of chemical and 

 physical constants are a special feature, which 

 should prove convenient for speedily identifying an 

 unknown oil or fat- — in fact, the present writer has 

 already found them useful. C. S. 



INCREASE OF AGRICULTURAL OUTPUT. 



(i) British Grasses and their Employment in Agri- 

 culture. By S. F. Armstrong. Pp. vii + 199. 

 (Cambridge : At the University Press, 191 7.) 

 Price 6s. net. 

 (2) Manuring for Higher Crop Production. By 

 Dr. E. J. Russell. Second edition. Pp. vi-l-94. 

 (Cambridge : At the University Press, 1917.) 

 Price 35. 6d. net. 

 (^) ' I "HE task of increasing home-grown food- 

 -■■ supplies has steadily forced itself to the 

 front as one of the key-problems upon the solu- 

 tion of which the issue of the war primarily de- 

 pends. The essential features of the problem are 

 by this time familiar even to the lay public, in so 

 far, at any rate, as they involve the ploughing up 

 of grassland and the planting of corn or potatoes. 

 It is not sufficiently realised, however, even by the 

 farmer himself, that this represents only one part 

 of the contribution which can be effectively made to 

 th(. desired increase of food production. The total 

 agricultural area of the United Kingdom is roughly 

 forty-seven million acres, of which some twenty- 

 seven million acres are under permanent grass, 

 whilst of the remaining area about six and a half 

 million acres rank temporarily as grassland, being 

 occupied at the moment by rotation grasses and 

 clovers, forming a transition crop in the arable 

 rotation. It is obvious that the utmost efforts in 

 bringing land under the plough can make only 

 relatively small inroads upon this immense acreage 

 of grassland, so that we must continue to depend 

 upon grassland for a very substantial contribution 

 NO. 2516, VOL. 100] 



to national food supplies. Moreftver, in proportion? 

 as the area of arable land increases and that of 

 grassland shrinks, the greater becomes the neces- 

 sity for devoting attention to the improvement of 

 the latter, in order that adequate grazing for live- 

 stock may be provided by the reduced area. 



It requires little acquaintance with farming to- 

 realise that a great deal of the existing grassland 

 is of very inferior quality, and it is common know- 

 ledge amongst agriculturists that a large propor- 

 tion of it could be considerably improved. Mr. 

 Armstrong estimates that fully 20 per cent., or not 

 fewer than 5,000,000 acres, of so-called grassland 

 is so infested with weeds and inferior grasses as 

 to represent comparatively worthless herbage. 

 What this means in terms of food production is 

 illustrated by estimates submitted to the British 

 Association in 191 5 by Mr. T. H. Middleton, 

 which showed that poor grazing land as it exists 

 to-day produces less than one-fifth of the meat 

 obtainable from the same area of average pasture 

 and little more than one-tenth of the produce of 

 the best grassland. 



The improvement of poor grassland must pro- 

 ceed along two broad lines. The first requirement 

 is the establishment of healthy soil conditions by 

 means of drainage, liming, and manuring, and 

 only when these have been secured can the other 

 half of the problem, the establishment of a herbage 

 of the more nutritious grasses and forage plants, 

 be successfully dealt with. A knowledge of the 

 characteristics of the different forage plants and 

 their relation to varying soil conditions is obviously 

 an essential part of the improver's equipment. 

 The subject, for which Mr. Armstrong uses the 

 unattractive name of "Agricultural Agrostology," 

 has received a considerable share of the attention 

 of the agricultural botanist, and Mr. Armstrong 

 has now endeavoured to present it in a form 

 adapted primarily for the agricultural student, but 

 not too technical to be of use to the practical 

 farmer, the seed merchant, and the rural school- 

 master. The major portion of the book is con- 

 cerned with the botanical characteristics of the 

 various species of grasses, special attention being 

 devoted to those species which are most abundant 

 or of greatest economic importance in the British 

 Isles. The treatment of this part of the subject in 

 the main follows conventional lines, but promin- 

 ence is given to points that have a special interest 

 for the student of agriculture. 



The latter portion of the book deals with the 

 practical problems presented by the grasses in 

 farm economy. Tlie agricultural value of grasses, 

 the valuation of grass-seeds, and the compounding 

 of seed-mixtures receive adequate treatment, whilst 

 a final chapter on the general treatment of grass- 

 land gives a brief summary of existing informa- 

 tion on a subject which demands much further 

 investigation. 



(2) In the improvement of grassland, as in the 

 increase of production on arable land, manuring 

 plays a part of vital importance, and it is in the 

 highest degree desirable that the farmer at this 

 juncture should receive trustworthy guidance in 

 the effective use of manures for all his crops. For 



