INTRODUCTlOrf. 7 



reductions. Slight discrepancies between aggregate sums and their 

 component quantities will also be apparent here and there, an inex- 

 actness which arises from the number of decimal places not having 

 always been carried out far enough. 



Our Author often quotes English agricultural writers, whose 

 weights, &c., he has always been at the pains to reduce into their 

 corresponding French equivalents. Not having at all times the 

 works referred to at command, the Editor was compelled to bring 

 back the French weight or measure into the corresponding English 

 one by calculation. Thus from not knowing the precise equiralents 

 adopted by M. Boussingault, some trivial discrepancy between the 

 computed and the original weights, &c., may have resulted ; but as 

 the quantities that have been treated in this way are especially im- 

 portant as relative, scarcely ever as absolute quantities, the error 

 where it occurs can be of no real consequence. Metres, centime- 

 tres, and millimetres have been reduced into English feet and inches, 

 assuming the metre as equal to 39.370 inches. Finally, and to 

 conclude our list of reductions, (would that it had been shorter !) 

 the degrees of the centigmde thermometer have been brought into 

 degrees of the only scale in familiar use among us, viz. Fahren- 

 heit's. 



In the translation the Editor has endeavored (not always with 

 perfect success) to be as little technical as possible, with a view to 

 the convenience of the general reader. In a very few places he 

 has even ventured slightly to condense the style of the original in 

 order to keep the volume within moderate dimensions, occasionally 

 throwing the information contained in a table into the text or nar- 

 rative ; and where the Author appeared to him to be forgetting the 

 rural economist in the mere chemist, as where for example he de- 

 scribes the special modes of preparing and purifying indigo, &c. he 

 has made bold to retrench details, and give the results or conclusions 

 only. All analyses bearing on the practical subject, whether it was 

 the soil that produced, the crop that was grown, or the animal which 

 fed on that crop, have been scrupulously retained. In conclusion, 

 the reader is earnestly recommended to read an admirable little 

 work, the joint production of Messrs. Dumas and Boussingault, en- 

 titled in the original, " Essai de Statique Chiraique des Etres orga- 

 nises," which has been presented in a clear English translation, under 

 the title of, " An Essay on the Chemical and Physiological Balance 

 of Organic Nature," and may be regarded as a most valuable intro- 

 ductory aid to the perfect comprehension of Boussingault's Philoso- 

 phy of Agriculture, and as a key to the more scientific and technical 

 portions of the work now submitted to the public. 



