EMBROIDERY.

437

are chosen, under the condition that in one of the positions of the parallelogram, theline c d which joins them passes through the point f; this condition may be fulfilled in

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satn e , * te num ^ er of manners, since the position of the parallelogram remaining Ihebe suffi 6 - SCe if we wished to shift the point d further from the point b', it wouldhave on Cle «^ to ^'ing the point c near enough to b", or vice versa; but when we?onseq U g e " xet * u P on the distance b'd, it is evident that the distance b" c is its necessary•s this- itprinciple upon which the construction of the pantograph rests°f fte posV su ® c knt that the three points /, and c be in a straight line, in one onlyW in evcrv nS °- f - the P a . rallel ° gram, in order that they shall remain always in a straightWe see^ P t °,f' t ' on w Ri c h can possibly be given to it.

!»>ts the ln ,. e fignre that the side b c, has a handle b" with which the workman° f the Pam CT -* ne m act .‘° 11 - To obtain more precision and solidity in work, the sidesv ertical plane a ' e i°' nec 'j so that the middle of their thickness lies exactly in theU ' ar to this nl° • Ptece of goods, and that the axes of the joints are truly perpendic-at this resu j ane J ,n which consequently all the displacements are effected. We arrivea ? nilable proiecr <l * m ” !" as ^ t0 t -* le ? u P er * or great cross bar n" an elbow piece d", having* JWUon » an « to which is adapted in its turn the piece d' 9 which receives in a