1846. 



GEx\F>SEH FARMER. 



277 



The FARMER'S AGRICULTURAL CHtMISTRY, com 

 piled from the best authors, and adapted to tho uso of 

 Schools. By M. M. Rodgers, W. D., Lyons, N. Y. 



We received a copy of a little 3 8 mo volume 

 of 100 pages, with the above title, some time 

 since ; but not being able, in justice to our 

 readers, to commend the work, in kindness to 

 the young author, we preferred to let it pass 

 without notice. Another copy has been sent us 

 by a friend of the compiler, with a note, which 

 in courtesy compels us to say something of the 

 • book. Of the 94 pages beyond the Introduction, 

 40 are taken bodily from other works ; and 54 

 are compiled mainly from the writings of Von 

 Thaer, Bergman, Chaptal and Davy, selecting 

 from these old authors, with singular infelicity, 

 such views on agricultural science, as have be- 

 come obsolete by reason of more recent discov- 

 eries. Speaking of nitrogen, on page 10, the 

 author says : " It exists in all animal substances, 

 and many vegetables : it may be obtained from 

 2)hosphorus.'" Tiiere are no less than three 

 mistakes in this brief sentence. Every tyro in 

 chemistry knows that pure fat is an " animal 

 substance," and that it contains not a particle of 

 nitrogen. The remark that '• many vegetables" 

 contain it, leaves the reader to inter that some 

 plants are destitute of this element ; which is 

 not true. Nor is it true that phosphorus (which 

 is itself a simple element,) contains nitrogen, or 

 that the latter " may be obtained" from the former. 



On the next page, to fix ammonia, in dung 

 heaps, the author, following Chaptal, recom- 

 mends the application of copperas and oil of vit- 

 riol. This was good husbandry in France and 

 England 40 years ago ; but since it has been 

 discoverad that gypsum is quite as good for that 

 purpose, and it can be had at one tenth the cost 

 of copperas, or sulphuric acid, it is plain which 

 should 71010 be recommended to farmers for fix- 

 ing ammonia. 



There is a chapter devoted to the " organs o 

 plants ;" yet nothing is said in regard to the cir- 

 culation of sap from the roots to the loaves, and 

 from the leaves to the roots again. Tliis is like 

 acting the play of Hamlet, with the part of Ham- 

 let left out! 



No department of chemistry is more valuable 

 in small alTairs than that which illustrates those 

 changes in organized substances which go by 

 the name of '' fermentation." On this subject 

 our author has just two sentences, the leading 

 one is in these words : 



" Fermentation is a peculiar decomposition or 

 transposition of the elements of a complex or- 

 ganic substance, by the agency of some exter- 

 nal force, different from ordinary chemical at- 

 traction, as heat, air, or contact with some other 

 body similarly affected." The other sentence 

 simply remarks that there are several kinds of 

 fermentation, as the "saccharine," "vinous" 

 *' acetic." And this is all the pupil is to learn 



of " fermentation" from a book, " adapted to 

 the use of Common Schools"! 



Cliapter 4 treats of " Rocks, and the forma- 

 tion of Soils." F«om what work the author's 

 remarks are compiled, it is difficult to surmise ; 

 for he says primary, as well as other rocks are 

 arranged in strata or layers. Tlie whole chap- 

 ter abounds in errors, showing that his author- 

 ities belong to an antedeluvian age in geologi- 

 cal science. If we are tocredit this book, "one 

 of the most productive soils in Sweden" con- 

 tains only three minerals " silica, alumina and 

 carbonate of lime ;" as though wheat and other 

 [)lanls can grow without potash, soda, magnesia, 

 sulphur, phosphorus, iron or chlorine ! This 

 statement is made on the authority of Bergmann 

 who wrote before analytical chemistry was born. 

 "Alumina is said to be the principal ingredient 

 in clay." This remark would pass for truth 20 

 years ago ; but now it is known to be almost im- 

 possible to find a clay soil which has one tenth 

 of its weight of alumina. Again it is stated, 

 (page 43.) that a "soil which contains 70 per 

 cent of sand is not adapted to wheat, but with 

 suiHcient manuring may produce barley.'''' This 

 was the opinion of Von Thaer in the last centu- 

 ry. We have shown in another article in this 

 paper that 90 bushels of wheat have been grown 

 on land containing over 80 percent of silica. 



On the subject of manures the authors says : 

 " As the carbon and nitrogen are derived from 

 the atmosphere, the benefit of manuring con- 

 sists exclusively in the supply of the salts and 

 soluble earfhy matters essential to the develope- 

 ment of the plants." This remark is taken 

 from Petzholdt, i^ our memory serves us, for no 

 credit is given. It carries theory farther than 

 facts and experience will warrant. 



Our criticism might be extended to any length 

 without exhausting the subject ; but it is unneces- 

 sary to go fardier. Had the author taken up 

 Johnston's Lectures on Agricultural Chemistry 

 and abridged the work to one third of its present 

 size, and adapted it to the use of Common 

 Schools, it would have commanded an extensive 

 sale as a school book, and great good would hava 

 resulted from the labor. But to compile a good 

 work from many authors implies a critical know- 

 ledge of all the sciences discussed, to discrinii' 

 nate accurately between truth and error. In his 

 Preface the author says : "I expect to escape 

 any unfair criticism inasmuch as my book is a 

 compilation, and I claim no originality." — 

 We trust he will not regard our criti- 

 cism as " unfair," for it is with extreme reluc- 

 tance that we have taken the trouble to point out 

 a few of the defects in the book. Dr. Rodgers 

 has considerable talent, but misjudges in attempt- 

 ing authorship, before he had studied for years, 

 and fully mastered his subject. The cheap and 

 easy method of making books by the use of 

 scissors instead of study, is the way to destroy. 



