s is the ruling of parallel lines. It consists in a the amount of work, and better, because there which they are applied, safer from accident the same throughout, and the distance between device for moving the rule over the surface of can be no variation in the movements of the than they otherwise… … A new volume of this useful and admirably , bolt, where he has to represent a thread, and T-square. The mechanical draughtsman is attached at one end, A’, as shown. The trig- conducted weekly will commence on the 13th | where he has now to move his square or tri- often called on to shade a section…
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