496 



NATURE 



[January 15, 1920 



tributes 51-4 per cent, of the world's wheat — a 

 sufficient explanation of the present scarcity. 

 North America contributes only 276 per cent. — 

 little more than European Russia. A chart is 

 then given to show the production in certain of 

 the States. North Dakota and Kansas easily 

 come first, followed by Nebraska, Minnesota, 

 Washington, etc. In yield per acre it is gratify- 

 ing to note that Great Britain stands first with 

 334 bushels, followed by Germany with 307, 

 France with 20-1, and the United States with 

 15 bushels. The cost of production per bushel 

 is stated to be lower in Great Britain than else- 

 where ; but to this English farmers might not 

 agree. The low position of the United States is 

 not to the author's liking: "Why European 

 countries produce larger yields an acre than the 

 United States is an important question for study. 

 Our natural resources are ordinarily as great as 

 those of European countries." 



America scores, however, in the efficiency of the 

 farm labourers and the use of machinery. The 

 portrait of Cyrus H. McCormick, who devised the 

 modern reaper and thus revolutionised the growth 

 of wheat, occupies a prominent place in the book, 

 and much space is rightly devoted to machinery. 

 A table is introduced showing how the time re- 

 quired of man labour to produce and thresh a 

 bushel of wheat has fallen since 1832 from 3^ 

 hours to 10 minutes only, and the cost of the 

 labour has fallen from lyf cents to 3^ cents. 

 Maize naturally claims a good deal of attention 

 as the most important farm crop in the States 

 in respect both of money value and of food value. 

 The United States contributes no less than 78 per 

 cent, of the world's supply; Iowa and Illinois are 

 the largest producers, but Indiana, Nebraska, 

 Missouri, and Ohio grow large amounts ; these 

 and Kansas constitute the famous " corn belt " of 

 the States. Of oats, as of wheat, Europe is the 

 ihief producer, growing no less than 61-2 per cent, 

 of the world's total; but in point of yield Ger- 

 many comes first with 574 bushels, followed by 

 the United Kingdom with 44-7, France with 30, 

 and the United States with 294 bushels. Later 

 chapters deal with animals ; the style is equally 

 good, and the matter equally interesting; a brief 

 history of the principal breeds of live stock is 

 given, with descriptions of their characteristics, 

 valuable features, and methods of treatment. 

 Next come sections on the soil, laying special 

 stress on physical properties, then sections on 

 fertilisers, and finally chapters on choosing a farm. 



Altogether the book is one of the most suc- 

 cessful for its purpose we have yet seen, and we 

 imagine it will make a vivid appeal to the 

 .American students for whom it is written. 

 NO, 2620, VOL. 104I 



{2) The other two books are more specialised. 

 Mr. Ekblaw writes about farm concrete, a subject 

 of which we are likely to hear much more in this 

 country in the future, for the making of concrete 

 requires only sand, cement, and grave' (or similar 

 substances) ; it can be moulded to almost any 

 shape and adapted to almost any farm building 

 purpose. The author deals with natural cement, 

 made by calcining and then pulverising natural 

 argillaceous limestone without preliminary mix- 

 ing and grinding ; and Portland cement or arti- 

 ficial cement, made by mixing finely ground argil- 

 laceous and calcareous materials in proportions 

 approximately of three parts of calcium carbonate 

 to one of silica, alumina, and iron oxide, then 

 calcining and finely pulverising. Portland 

 cement, it is interesting to note, was invented 

 by an Englishman, Joseph Aspdin, in 1824, and 

 for many years we led the wav in its manufacture ; 

 but now the United States leads, surpassing all 

 other countries both in manufacture and in use. 

 Several varieties of concrete are made, but the 

 constituents are always cement, a fine aggregate 

 (usually sand) and a coarse aggregate (usually 

 pebbles or broken stones), the purpose of the 

 fine material being to save cement by filling up 

 more closely the pore spaces ; an apparatus called 

 the voidmeter is described for estimating the 

 amount of pore spaces of different materials. Re- 

 inforced concrete as used for buildings is concrete 

 in which steel or other material is embedded to 

 increase its strength. It was invented bv a 

 French gardener, Jean Monier, in 1876, and has 

 proved very successful. Its use is still somewhat 

 empirical, the underlying principles not being 

 quite understood, but sufficient useful knowledge 

 has been gained to reveal its great promise for 

 the future. 



Great stress is laid on the fire-resistant pro- 

 perties of concrete for building purposes. The 

 building regulations in New York are severe ; a 

 building to be considered fireproof must with- 

 stand when fully loaded a temperature of 1700° 

 for four hours, and then be subjected to a stream 

 of water discharged from a ij-in. nozzle under 

 a pressure of 60 lb. without failure. A number 

 of systems of reinforced concrete have success- 

 fully passed the test. 



The rest of the book is devoted to the special 

 purposes for which concrete can be used on the 

 farm. For building purposes it takes the place 

 of both brick and wood ; it can be used for 

 buildings, posts, mangers, floors, yards, and 

 the farmhouse itself. The book will be of great 

 interest to country builders and estate agents who 

 wish to build as cheaply and quickly as possible. 



(3) The last book on the list, "Peach-growing," 



