Biographical Notices of Thomas Newcomen and John Caw-
ley, 144. First atmospheric engine, 146. Introduction of
safety-valve by Desaguliers, note, 148. Switzer's account of
Newcomen's invention, note, 150. Sniffing clack, 153 New-
comen's boiler, 155. Griff engine, 156. Condensing by injec-
tion, 157. Bradley, 158. Engine for Mr. Balle, 59. Hum-