1922.] Trial of Tikbkb Jacks anh a Moxkky Winch. 369 



A TRIAL OF TIMBER JACKS AND 

 A MONKEY WINCH. 



A Report* was recently published by the Ministry on hedge 

 and stump clearing devices, containing the results of tests con- 

 ducted at Long Sutton in Hampshire. An abstract of this report 

 appeared in the Ministry's Journal, April, 1922. page 6. One 

 of the devices tested was a mechanical jack, manufactured by 

 Messrs. Trewhella Bros., of Birmingham, the results with which 

 were far from satisfactory. Messrs. Trewhella therefore 

 requested the Ministry to subject the device to a further trial, 

 and with the concurrence of the Hampshire Agricultural Educa- 

 tion Authorities advantage was taken of a test of sub-soiliog and 

 tillage machinery recently held at Sparsholt Agricultural Institute 

 near Winchester, to obtain further data. Conditions were 

 obtained as far as possible similar to those in the former trial 

 at Long Sutton, and a monkey winch for timber removing manu- 

 factured by the same firm was also included in the test. Much 

 better results were obtained in the later trial with the jack, and 

 the device can be regarded as an economic unit worthy of con- 

 sideration by any farmer desiring to clear timber over a 

 protracted period. 



The Test Ground. — The plot upon which the jacks and winch 

 Worked was level and consisted of light loam, with chalk at a 

 depth of from 1 ft. to 1 ft. 6 in. In consequence all the timber 

 was shallow rooted. The test lasted over a period of two days. 

 During the first day. the monkey winch only was tested, and 

 on the second day the jacks were tested. The timber consisted 

 of elder, hazel and maple stools and blackthorn and maple 

 trees. 



Data were obtained under the following heads : — 



1 . Weight and volume of timber, size of crater, and quantity 



of earth displaced. 



2. Number of hands required to operate the device. 



3. Time taken to prepare for work. 



4. Capital cost, depreciation, and maintenance. 



5. Comparative degree of skill needed to work the device. 



'*>. Mechanical design and construction, and general efficiency 

 of the device. 



* Miscellaneous Publications No. 35. Price 2/6. pOBl £ >■»•. from the 

 Ministry. 10. Whitehall Place. London. S.W.I. 



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