72 TECHNOLOGY. 
per cent. of the power applied. Pl. 15, jig. 24, is an elevation of a wheel 
arranged in this manner; jig. 25 a plan; jig. 26 a section of the wheel upon 
a larger scale; jig. 27 shows the bearing of the main shaft; 7g. 28 a vertical 
section of the water passage ; jig. 29 a view of the small gate; a is the flume; 
B the wheel secured to the shaft, c; p, the stationary curves which conduct 
the water to the wheel, and are secured to a nave made fast to the vertical 
post, F, im such a manner as to be easily raised or lowered ; @ is a gudgeon 
made fast by the wedge, x, to the vertical post, 5, to which the wheel, Bz, is 
hung. The oiling of the gudgeon is accomplished by means of the canal, y, 
bored through the shaft, c, of the wheel (jig. 26). The guide-curves serve 
also the purpose of a gate to admit the water, and are raised and lowered for 
that purpose in the following manner (jig. 24). The rods, n, passing into 
the opening, m, of the nave carry the guide-curves ; these rods, by means of 
the joint, op, and levers, pq, are connected with the rod, s, passing through 
a stuffing-box, and moved by the lever, 7, and vertical rod, ¢. 
3. Grinpinc MILts. 
With mills as commonly constructed and arranged every one is supposed 
to be familiar; having therefore already noticed the power by which 
they are driven, we will turn our attention only to some important im- 
provements which have been made in the United States during the last 
fifteen years, and which are now generally introduced into Germany and 
other parts of Europe. Amongst the advantages which these improve- 
-ments possess are the following: Ist. A much larger proportion of superfine 
flour is obtained from the grain. 2d. The flour is better adapted to keeping 
and to transportation to hot climates, being in a great degree deprived of its 
moisture, and this without kiln-drying the grain, which has not been found 
fully to answer the purpose. 3d. The compactness and general arrange- 
ments of the machinery, together with the use of cast-iron for the 
mill-shafts and gearing, materially lessens the friction of the running 
parts, the frequent recurrence of breakages, and the consequent cost of 
repairs. 
In pl. 16 is a system of mills upon the American plan for six run of 
stone; fig. 1 is an elevation, jig. 2 a vertical section through the main 
_driving-shaft, jig. 8 a vertical section perpendicular to the latter, jig. 4 a 
section showing the disposition of the stones, jig. 5 a portion of the ring 
supporting the vertical shafts of the stones, jig. 6 a view from above, jig. 7 
a view from above of the ring upon which the separate shafts are supported, 
jig. 8 a vertical section of the mill-bush in the stationary stone, through 
which the vertical shaft which drives the upper stone passes, fig. 9 the 
horizontal section of the same; jig. 10 vertical section of the upper portion 
of the boxes in which the mill-shafts run, with the apparatus for raising the 
same; fig. 11, plan of the same; jig. 12, horizontal section immediately 
above the mill-spindle, jig. 13, horizontal section immediately above the 
base of the column ; jig. 14, horizontal section immediately over one of the 
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