LOOM AND SPINDLE—HOOPER. 669 
the needle points the needles will be pressed inward, push the hooks 
off the bars of the griffe, and the block will rise without them. 
It follows, then, that if we interpose between the needle points and 
the side of the cylinder, as it presses the needle board, a card per- 
forated according to an arranged design, wherever a hole is covered 
by the card a needle will be pressed in, and consequently a hook will 
be pushed off the griffe bar and left down as the block rises. 
Each card, therefore, affects, in one way or another, every hook 
. in the machine with its necking cords and leashes; and these, of 
course, determine the rising or remaining down of every thread of 
the warp from edge to edge of the web. 
At the back of the machine a shallow box is fitted, containing 400 
small spiral springs, one for each needle. When. therefore, any 
needle is pressed inward by the 
card on the cylinder, its oppo- 
site end is forced into the spring ,/ 4 \ Bath 
box, but as soon as the pressure | = Vi ip he 
is relaxed the needle, driven VA 
back by the spring, regains its 
normal position, holding the 
hook upright. 
The mechanical contrivances 
by means of which the cylinder 
is moved, pressed against the 
needle board and rotated as the 
block rises and descends, are 
most ingenious, and subject to 
a great deal of variation. They 
are, however, not essential to 
the principles of the machine Fic, 53.—Jacquard cylinder and cards. 
and can be passed over. But 
the method by which the perforated cards are adjusted to the cylin- 
der and interpose between it and the needle board must be explained. 
Figure 53 shows a detached cylinder and four cards punched with 
a pattern called a four-lined twill. This pattern repeats on every 
four lines; accordingly only four cards are needed to weave it. At 
the ends oF the cylinder, close to the perforations, pegs are fixed and 
holes matching these pegs in size and position are punched in the 
cards. ‘These pegs hold the card in its proper place, so that its per- 
forations correspond exactly with those of the cylinder. 
Each side of the cylinder as it rotates, being covered with a card 
held close to it by two elastic bands will press against a different set 
of needles at each of its four movements. The fifth movement, of 
course, brings the first set of needles again into play. When, how- 
ever, as is generally the case, more than four lines of design are re- 
s$f53 i ffedies es 
