54

CALICO PRINTING.

C.

CALCIUM. The atomic weight of this element being an important point, both ® sto pure chemistry and the chemical arts, has been the subject of innumerable research®^Very lately Berzelius , in the .dnnalen der Chemie nnd Pharmacie, XLVI. p- 24L Acollated the most recent results of the analysis of other philosophers with his orvn; a .while Dumas, Marchand, and Erdmann estimate the weight at 20 , that of hydrogen^’or 250 oxygen=100, he tinds it ought to be, as compared with the latter, 251*9; ato the former, 20-152.

CALICO PRINTING (4 -color machine). Of this beautiful and effective meeba®ism an accurate section is exhibited at p. 220 of the Dictionary . The outsidems gear is shown in Jig. 16., where A, A, is a part of the two strong iron frames

Scale r

cheeks in which the various rollers are mounted. They are bound t0 S w jth &rods and bolts a, a, a. B, is the large iron pressure cylinder, which ^ (he si®gudgeons in bearings or bushes, which can be shifted up and down in , sl ° turn 1cheeks A, A. These bushes are suspended from powerful screws, o,brass nuts, made fast to the top of the frame A, as is plainly shown ^ c ylind er 'These screws serve to counteract the strong pressure applied beneaththe engraved cylinders D, E.

ji i j. j.. their op eI> ®

C, D, E, F, are four printing cylinders, named in the order ol gcr eWThey consist of strong tubes of copper or gun metal, forcibly thrust J' j a9 t cyhupon the iron mandrels, round which as shafts they revolve. The ju s or j z ontal s j .ders, C and F, are mounted in brass bearings, which may be shifted in w ;th a ' Jjof the frame A. The pressure roller B, against whose surface they e j eva ting ®‘jlittle obliquity downward, may be nicely adjusted to that pressure by » ^ geoB ietndepressing screws. By this means C and F can be adjusted to Uprecision, and made to press it in truly opposite directions.

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