Scientific American, Vol. 21, No. 21 (1869)
This is a weekly issue of Scientific American from 1869, an American periodical for engineers, inventors and mechanics, printed in New York with mechanical diagrams and short technical notices. Its pictures are line engravings of boiler safety fittings, a steam road engine, a lamp and a clamping tool, showing crisp hatched shading and labelled cutaway views a designer could use for vintage technical diagrams.
