MECHANICS AND USEFUL ARTS. 71 



are represented by letters, as CVIII. for one hundred and eight, and so on, 

 and the capitals are designated by a single dash at the top of the requisite 

 letter. 



Each key, when struck, acts upon an independent lever within the 

 machine, attached to a little elbow and arm, on the end of which is the 

 corresponding letter-type, which now strikes the under sheet of paper and 

 presses against the platin on the suspended steel rod, so that, the inked tape 

 being between the two sheets of paper, the blow leaves the letter printed on 

 each, namely, on the upper side of the lower sheet, and, of course, on the 

 lower side of the upper, when brought in contact with the tape. 



As the printing goes on, the paper moves steadily to the left; and when 

 the line is within four letters of its end, a little bell rings spontaneously to 

 notify the writer that he must touch a spring which pushes the sheet up the 

 .space of one line, and back, to begin again; and as the printing of the new 

 line goes on, the paper travels back another line; and so on, till the page is 

 completed. 



The letters can be formed of any sized type, engraved for the purpose, 

 and suiting the taste of the purchaser. Those who use this " "Writing 

 Printer" will be enabled to strike off two copies in less time than is re- 

 quired to produce one with the pen; and for clergymen, merchants, editors, 

 and literary men, it must prove of great value. The price of the machine 

 is one hundred dollars, which is as cheap as a good sewing-machine, while 

 the art of working it is not more difficult. The inventor is S. W. Francis, of 

 New York City. 



ON THE INFLUENCE OF SCIENCE ON THE ART OF CALICO PRINTING. 



The following lectures on the progress of calico printing are communicated 

 to the London Engineer by Prof. F. Grace Calvert, F. R. S. 



Pencilling and Block Printing. During the early part of this century, the 

 production of designs upon calico were performed by means of hand-blocks, 

 made of sj^camore or pear-tree wood. The face of the block was either 

 carved in relief into the desired pattern, like ordinary wood-cuts, or the fig- 

 ure was formed by the insertion, edgewise into the wood, of narrow strips 

 of flattened copper wire, and the patterns were finished by the hand labor of 

 women, with small brushes called pencillings. Owing to a strike amongst 

 the block printers, in 1815, to resist the threatened introduction of machin- 

 ery, great efforts were made on the part of the employers to render them- 

 selves independent of hand labor; and the result has been the gradual 

 introduction of cylinder printing. 



Engraving. The first kind of roller used was made by bending a sheet 

 of copper into a cylinder, soldering the joint with silver, and then engrav- 

 ing upon the continuous surface thus obtained. 



The second improvement consisted in producing the pattern on copper 

 cylinders obtained by casting, boring, drawing, and hammering. In this 

 case, the pattern is first engraved in intaglio upon a roller of softened steel 

 of the necessary dimensions. This roller is then hardened, and introduced 

 into a press of peculiar construction, where, by rotary pressure, it transfers 

 its design to a similar roller in the soft state, and the die being in intaglio, 

 the latter, called the "mill," is in relief. This is hardened in its turn, and, 

 by proper machinery, is made to convey its pattern to the full-sized copper 

 roller. This improvement alone reduced the cost of engraving on copper 



