R. A. Daly — Machine-Made Line Drawings. 229 



twenty-five shuttles made for such a machine (each shuttle 

 bearing ninety characters and including the lettering for one 

 of twenty-six different languages), will give an impression 

 suitable for photographic reproduction. Each shuttle can be 

 placed in the machine ready for work in a few seconds. The 

 usual silk ribbon gives a " woolly " line, and is far less satis- 

 factory than the carbon ribbon. A highly calendered and 

 high- grade linen paper of a medium to heavy weight or a thin 

 Bristol board may be recommended. Often more than one 

 impression of the key is necessary to obtain the required depth 

 of tint for photography ; such repeated impressions can be 

 made at great speed by employing a back spacing key. Care 

 must be taken not to smudge the carbon of the completed 

 printing. 



2 



W. by N. E. by S. 



The accompanying cuts serve to show something of the 

 method as applied to geological diagrams. The diagram 

 (fig. 1) of alphabets and legends has been reduced to four-fifths 

 of its original diameter. The legends are intended to repre- 

 sent a few examples of those possible with the machine. They 

 can be indefinitely increased in number and varied in design 

 by the engraving of new characters on the shuttle, and by 

 using various permutations and combinations of the existing 

 characters. The section (fig. 2) is reduced to about one-half 

 of its original diameter. It was copied from Harker's section 

 of a composite triple sill published in " The Tertiary Igneous 

 Rocks of Skye" (Memoir of the Geological Survey of the 

 United Kingdom, 1904, p. 204). The result represents the 

 saving of from seventy-five to ninety per cent of the time 

 required by a draughtsman to duplicate the drawing. 



It is to be understood, of course, in the preparation of a 

 diagram that an outline drawing is first prepared, and that the 

 spaces thus formed are filled with the symbols shown in the 

 legends, by means of the machine. 



Ottawa, Canada. 



