Note 1 — INTRODUCTION.
Reading edition
The smallest working steam engine that the writer has ever heard of has a net weight of 4 grains. One hundred such engines would be required to weigh one ounce. The bore being 0·03 in., and stroke1/32 of an inch, r.p.m. 6000 per min., h.p. developed1/489000 ("Model Engineer," July 7, 1910). When working it hums like a bee.