612 TJie Trials of Grist Mills and Disintegrators at Plymouth, 
flutings being by preference parallel to the axis of the roller, 
while the latter are inclined thereto." 
Hardley's mill very soon came to be considered the best 
general grinder and crusher, since it dealt effectively and expe- 
ditiously with a variety of substances, absorbed little power, was 
constructively veiy simple and strong, while the facilities it offered 
for adjustment and manipulation left nothing to be desired. 
As a consequence of its obvious merits, the Hardley mill was 
exploited with a great deal of energy, and made in considerable 
numbers by Messrs. Picksley & Sims, of Leigh, more than 
twenty-five years ago. The mill, however, ultimately declined 
in public favour, giving way to various forms of disc-grinders, 
and that for reasons which, at first sight, are somewhat obscure. 
Woodroffe's mill, constituting a return to practice now more 
than a quarter of a century old, is, indeed, a case of mechanical 
" atavism," and, in view of its excellent performance at Plymouth, 
it may be interesting to inquire what it was that buried the 
Hardley mill before it was yet, mechanically speaking, dead. 
The answer to this question is a purely technical one. It is 
a difficult task to make a satisfactory chilled and grooved roller, 
even of small dimensions, without the use of much more refined 
methods than were generally in vogue either in the foundry or 
in the fitting-shop twenty-five years ago ; and the value of the 
Hardley mill depends entirely upon how good a "job" is made of 
the roller and concave. On the other hand, chilled discs are easily 
and cheaply produced, even in the most rudimentary foundry, 
and it happened that, while Messrs. Picksley & Sims made no 
effective arrangements for producing chilled rollers and concaves 
of high perfection, the disc-mill maker, working under less 
stringent mechanical conditions, became first a formidable, and 
lastly a deadly, competitor with the Hardley mill. It is because 
Woodroffe is now taking great pains, both in founding and 
grinding, to make a " good job " of his chilled roller and breast, 
besides putting sound work into his concave hinges and feed 
adjustment, that roller- and breast-grinding made such a good 
show at the Plymouth trials. But for the loss of some points 
on cost and sample (particularly in oats), the Woodroffe machine 
would have run an even closer race than it did with Corbett 
& Son's mill. In the result, however, it obtained the second 
prize. 
2'i/pc V. Conical roller and hreast-grinding with cndwite 
delivery of the meal. — Messrs. Barford & Perkins's well-known 
" Felton " mill (No. 3363) consists of a conical grooved roller 
some 20 inches long, and tapering from 9£ inches to 7| inches in 
diameter, cast of hard white metal, but not chilled. The cone 
