580 Report of the Trials of Ploughs, Harroivs, ^-c, at Hull. 
instead of 20, as would be the case according to the ordinary 
method of fixing by screw-head, teeth, and nuts. The following 
illustrations exactly describe the mechanism. This system was 
Figs. 78 and 79. — Ulustrations of the collar and tube arrangement of 
Teeth and Beams in Harrows. 
Fig. 78. Fig. 79. 
Fig. 78 is a view of one of the teeth and parts of the beam, in order to show 
the joint ; and Fig. 79 is the same as Fig. 78, but with the different parts 
detached, so as to show each separately. It will be seen by Fig. 79 that the 
tooth A is formed with a grooved head, which fits on the side of the beam b, and 
clips it tiiihtly, thereby throwing the strain on tlie tooth directly on the beam ; 
the bolt D which x^asses through both, merely serving to maintain the different 
jiarts in their relative position to each other, c is a tube or collar through 
■which the bolt d, which secures each row of teeth, passes, and which serves to 
maintain the harrow beams at their proper distance from each other ; the whole 
when put together and the bolt tightened up by the nut E, being almost as 
rigid as if in one piece. 
adopted by Messrs. Larkworthy, and Cambridge and Parham ; 
and as neither were noticed by the Judges, it may be concluded 
that the work done by them was not as satisfactory as that done 
by others.* Referring to the Judges' log-book, I find that whilst 
W. Asliton's heavy harrows in Class 4 were credited with 800 
marks, those of Messrs. Larkworthy and Co. reached only 700, 
and Messrs. Cambridge and Parham were 600. Confining our 
attention to the mechanical qualities, the first and second prize 
implements in Class 18 will be found credited with 250 and 
240 marks respectively, whilst Larkworthy's and Parham's were 
valued at 200 ; so that it is clear that the Engineers considered 
this arrangement the less perfect. 
* Since Ihc above was written I liave learnt that the Judges were imauimous in 
tlioir ajjproval of this principle, Cbpecially as rcijards the plan of securing the 
tisture of the tines. 
