328 



SCIENCE. 



[N. S. Vol. IX. No. 218. 



The detailed exposition of Grassmanu's system 

 is excellent and will be welcomed by all who 

 wish to assimilate the ideas of that great master 

 of space-analysis. The last book of the present 

 volume is on the application of the calculus of 

 extension to geometry, and it is evident from 

 the fourth chapter, entitled ' On Pure Vector 

 Formulae,' that the author considers vector 

 analysis to be supplementary to quaternion 

 analysis. They are not the same thing ; and 

 both gain when it is perceived that they are 

 not redundant, but supplementary to one an- 

 other. 



In conclusion, the work reflects great credit 

 on the author and on the Cambridge University 

 Press ; it is likely to lead to further advances 

 in Universal Algebra, not only by what it lays 

 down, but by the questions which it brings for- 

 ward for discussion. 



Alexander Macfaelane. 



The Principles of Agriculture. By L. H. Bailey. 



New York, The Macmillau Company. 1898. 



Pp. XX + 300. 



' Principles of Agriculture,' by Professor L. 

 H. Bailey and his associates in Cornell Univer- 

 sity, is a new volume in the Rural Science Series 

 and in many respects is the most important one 

 of the series, as it serves as an introduction to 

 the others. The book is intended to be used as 

 a text-book for schools and rural societies, but 

 it Avill prove interesting and valuable for the 

 agriculturally inclined who have had little or 

 no training in the natural sciences. It is essen- 

 tially a book for beginners, and as such serves 

 its purpose better than any of the small hand- 

 books which have attempted to treat of the ele- 

 mentary principles of agricultural science. 



The volume is edited by Professor Bailey and 

 some of the chapters are written by him ; the 

 remaining chapters are written by his associates, 

 who are specialists in the departments of which 

 they have written. At the end of each chap- 

 ter are suggestions which serve to elucidate the 

 text for readers whose knowledge of natural 

 science' or of rural affairs is scanty, and also 

 give useful hints for teachers who may use the 

 volume as a text-book. 



la the introduction we are told that ' ' agricul- 

 ture is not itself a science, but a mosaic of many 



sciences, arts and activities, or, a composite of 

 sciences and arts, much as medicine and surgery 

 are. * * * But the prosecution of agricul- 

 ture must be scientific." The aim of the book 

 is to deal with ' fundamentals ' rather than ' in- 

 cidentals. ' ' ' The mistake is often made of 

 teaching how to overcome obstacles before ex- 

 plaining why obstacles are obstacles. » «■ * 

 The purpose of education is to improve the 

 farmer and not the farm." Would that more 

 of our farmers could see the truth contained in 

 these statements. 



The book opens with a brief treatment of the 

 formation of the different kinds of soils. On 

 page 27 the author says : " The profit in agri- 

 culture often lies in making the soil produce 

 more abundantly than it is of itself able to do." 

 On page 202 : "In intensive and specialty farm- 

 ing manures may be bought." These state- 

 ments are true, but do not consist well with 

 what is said about ideal agriculture on page 2. 

 Inorganic compounds are explained as those 

 which are not produced by living organisms, 

 and phosphoric acid is given as one example, 

 notwithstanding that a large amount of phos- 

 phoric acid used in commercial fertilizers is 

 made from bone. Although the chemists call 

 it an inorganic compound, yet because it is 

 found in the remains of animals the reader who 

 has had no knowledge of chemistry might be 

 puzzled until some further explanation was 

 made. 



The second chapter, which is written by Pro- 

 fessor Spencer, shows what is meant by ' tex- 

 ture ' of the soil, why good texture is important 

 and how to obtain it. That " the texture or 

 physical condition of the soil is nearly always 

 more important than its mere richness in plant 

 food " is a fact not recognized by some tillers of 

 the soil. 



The ' moisture of the soil ' and ' tillage ' are 

 next treated in a brief and creditable manner. 

 Several figures are given to illustrate the art of 

 plowing and one of an ' ideal general purpose 

 plow.' All plowmen will think that this imple- 

 ment might be improved upon, but the low 

 handles should be appreciated by everyone. 

 The handles of many plows are too far from the 

 ground. 



Chapters IV. and V, treat of enriching the 



