506 
Report on the Trials of Implements at Oxford. 
Section XI. — Guano Bkeakehs. 
Prizes withheld. 
Tlic sum of 20?. was placed at the disposal of the Judges. The imiilements 
are of little practical use to a farmer, because the operation they perform is not 
of frequent occurrence, and the advantage of mechanism over manual labour 
is not suflicieutly great to render outlay desirable ; for these reasons we think 
it rather fortunate than otherwise that the two machines that were tried worked 
so indifferently that the Judges withheld the prize. The exhibitors were P. 
& W. Hobbs, Basingstoke, and Thomas Corbctt, Shrewsbury. Messrs. Hobbs's 
mill was cone shaped, witli a series of wrought-iron sections, carrying four and 
three teeth alternately. Tliese sections are of diiferent thicknesses, and the 
bottom of the mill is formed in divisions to fit the teeth, hence the guano 
lumps entering at one end are first broken roughly, and then finer until the 
manure is delivered as a fine powder. There is a screen attached to the hopper, 
and worked by a cam, this separates the dust. 'I'hree men were required to 
manage the mill ; and we feel certain that two men with a wire sieve could 
do as much and as well without an outlay of bl. 15s. The machinery is too 
elaborate for the work required to be done. 
Corbett's machine also described as a novelty, consists of an 8-in. fluted 
roller, working against a shell kept in place by a weight and lever, so if a stone 
or any metal enters, the shell gives way and lets it through. The end of the screen 
rests on the roller, and receives vibrating motion from the inequalities of the 
fluted surface. This mill failed to finish its work, small pieces of guano 
working into balls would not go through, notwithstanding all the efforts of 
an assiduous attendant. 
From this experience, and looking at the comparative inutility of such au 
implement, we venture to suggest that this prize should not be repeated. 
There was no competition in this section. Messrs. Headley and Tye's 
articles, although entered for trial, were not put into a condition for working, 
and hence were struck out. Messrs. E. R. & F. Turner exhibited machinery 
which appeared highly suitable, and for which they have had a consider- 
able demand. The coprolites are first reduced in a crushing-mill, which, 
as more expeditious and less costly, is preferable to mill-stones sometimes 
employed. One pair of rollers will reduce sufliciently fast for three pairs of 
stunes to grind. The crusher consists of two powerful rollers of chilled 
iron, kept in contact by levers with balance weights. It is frequently worked 
in conjunction with the grinding-stones, and is then driven from the same lay 
shaft to which the pinion with disengaging clutch is attached. The gearings and 
framework are particularly strong. The coprolites are reduced in the crushing 
mill to a considerable degree of fineness ; some coarse particles, however, remain, 
and it is an open question whether it would not answer to separate these by a 
fine sieve and recrush. It would certainly relieve the stones and expedite the 
grinding, which is desirable. The mill is on precisely the same principle as 
their corn-mill already noticed, only much more powerful. The stones are 
4 ft. 6 in. in diameter, of best French burr. When it is desirable to drive 
the crasher and not the mill, the latter can be thrown out of gear by raising 
the pinion on the stone-s])indle effected by a lever. The driving-wheel or 
lay-shaft is geared with well-seasoned wood cogs, and works with iron pinions 
Section XII. — Copiiolite Mills. 
Award. 
£1C. 
