Wheel and Swing Ploughs. 



147 



merits have been chiefly confined to the ploughs described in the 

 former part of this Essay. 



Of the Suffolk and Norfolk wheel-ploughs on high wheels and 

 gallowses, adapted as they may be to light soils, they are necessarily 

 cumbersome, and constructed with so many conflicting forces that 

 much depends on the skill of the ploughman to adjust them. I 

 have noticed that it is continually necessary to raise or deepen the 

 gallows, which require alteration, on taking out or setting in, each 

 furrow, with beam-bolts, &c., regulating the action to and from 

 land, and consuming much time in their repeated adjustment. 



The Kentish ploughs are on a somewhat similar construction,, 

 with high gallowses and wheels, but larger and stronger than the 

 before-mentioned : these are said to be necessary to resist the heavy 

 stones which they continually encounter. They are confined to 

 their respective localities. While it is questionable whether they 

 will be much longer retained there, it is certain they will not 

 become general in other parts. 



The facts detailed in this paper are founded on practical and 

 careful experiment. The result arrived at in my own judgment 

 is forced upon me by conviction, and I have only to add that I 

 shall be equally open to the influence of opposing facts^ if founded 

 upon actual and well-attested experiment. 



XIV. — Account of Liquid Manure. — An Essay to which the 

 Prize of Ten Sovereigns was awarded in July, 1839. — By 

 CuTHBERT W. Johnson, Esq., of Gray's Inn, Barrister-at- 

 Law. 



Liquid manure, the subject of our Society's premium, is not a 

 mode of fertilizing the land altogether of modern origin^ for a 

 fermented mixture of water and night-soil has, from a very early 

 period, been employed by the Chinese farmers; those of Italy cer- 

 tainly practised irrigation in the days of Virgil (Georgics, book i., 

 V. 106-9), and Cato adds that they employed a mixture of grape- 

 stones and water to fertilize their olive-trees (book xxxvii.). 

 Columella praises very highly the use of putrid stale urine for 

 vines and apple-trees (book ii., c. 15), commending also the lees 

 of oil for the same purpose. More modern agricultural authors 

 have united in praising various liquid preparations ; thus Evelyn 

 (whose ingredients most of the authors recommend), in his Trea- 

 tise on Earth (p. 123-60), gives several recipes, some of which 

 have served as the basis for recent modes of preparing liquid ma- 

 nure, such as the dung of cattle, urine, salt and lime, and nitre. Of 

 these artificial mixtures, salt one part, and lime tAVO parts, mixed 

 together and allowed to remain in aheap for two or three months 



