\ 
164 REPORTS FROM THE SECTIONS. 
block, the name, or any remarks to be printed with it, are en- 
graved, and it is ready for the finishing process, which is rubbing it 
very lightly with water-of-ayr stone and water, to remove the burr 
raised at the edges of the lines and holes. Care must be taken 
not to make the surface uneven with the stone. 
Tf the block is small, 4 or 5 inches each way, it may be printed 
in an ordinary letter-book press, and in that case the metal may 
be any convenient thickness; but if it is large it must be type 
high—that is, as thick as the length of an ordinary type letter. 
If too much ink is used in the printing the lines fill up and will 
not print ; if too little ink the prints will not be black. Similar 
defect may be caused by want of power in the press. I have 
obtained prints in this way as good as the best lithographic 
work. 
telescopic power. Now in a star cluster, of which I have recently 
made a map, this star dust is a conspicuous feature ; the more 80 
how exhibited will illustrate what is meant 
A modification of this method would print nebule white on 4 
black ground. 7 
So far I have only spoken of type metal, but other metals may 
_ be used, and I have found sheet-lead very easy to work, and quite 
f : only diffi 
the stars are in the right places and of the proper relative ener 
tudes. The maps being printed on dry paper are subject 
minimum of distortion from expansion or contraction 
.. i ae 7 
per. And lastly, the block itself can be kept as a peer and 
