Observatiofis on Liebig's " Organic Chemistry" l^l 



decompose alike. A little further fermentation in the manure 

 might have made more of it soluble, without a corresponding 

 loss ; and in such analysis chemistry might greatly aid practical 

 men. The dung of high-fed animals is always allowed to produce 

 most benefit ; there will be most undigested matter in the ex- 

 crement, and from feeding on grains most nitrogen. Dr. Liebig 

 says, fat animals have most free nitrogen. 



Oils are valuable as manures ; they will keep long, as they are 

 not easily decomposed, and are rendered soluble by being mixed 

 with potash and soda, in which state they are taken up as soluble 

 soaps, and their carbon, &c., assimilated in the plant. The un- 

 common fertility of bleaching-greens, when newly broken up, 

 is a proof of this. I have seen soils not otherwise rich pro- 

 duce immense heads of cauliflower at first breaking up, which 

 could not be made to do so afterwards ; cauliflower is well known 

 to require both rich soil and extra manure, yet did the soap- 

 suds in a bleaching-green suflice to impart that quality to a poor 

 black sandy soil. The lixiviated ashes of soapers' waste are 

 likely to contain both oil and alkali, and the contents of the 

 washing-tub should never be thrown away ; they are soluble, 

 and not easily evaporated, and may be spread on the land, or 

 thrown on the dung heap ; when thrown in the ashpit they are 

 absoi'bed by the cinders and lost. It would be advantageous to 

 mix oily substances with soda or potash, before committing to 

 the soil ; if there is much lime in the soil, it is apt to form an 

 insoluble soap between the oil and lime, while the other with 

 the soda and potash is soluble. We see hence the benefits of 

 the scourings from woollen manufactories; they consist in the 

 oil and alkalies of the soap and wool, and the urine used in such 

 processes ; it has been used in this quarter with great effect. 

 Hair, wool, and skin, from tanyards and curriers' works, contain 

 gelatine, albumen, and other principles, similar to those in bones, 

 which have already been treated of; the oil used by the latter 

 will be beneficial, the tannin and lime of the former detrimental. 

 Bones are best unboiled, boiling removes much of the gelatine 

 and nitrogen. Horn contains more animal matter than bones, 

 and is similar ; the parings of horses' hoofs are apt to contain 

 filings of iron, which are prejudicial, as they oxidate. Blood 

 contains most of the animal constituents, and must be valuable ; 

 the colouring matter is supposed to be mostly different from 

 iron. The uses of the waste of glue manufactories we have 

 already quoted from Dr. Liebig. Of the refuse of other manu- 

 factories the operation may be known, when we get a know- 

 ledge of their contents. Rape cake contains vegetable matter, 

 holding nitrogen in a state of decay, and oil ; if potash, or 

 ashes of small branches and leaves of plants, were mixed, they 

 would render the oil soluble, and retain any carbonic acid or 



