Mr Whitelaw on a New Escapement . 27 
the magazine B can take place in this position ; and if we again 
suppose the hollow turned round to d , there is still no commu- 
nication. In short, Mr Forrest’s invention in this respect is so 
excellent, that even with the greatest neglect and carelessness 
there is no danger. 
The quality of the priming powder is the same as used for 
Mr Forsyth’s patent, S parts of the oxymuriate of potash, 1 of 
sulphur, and 1 of charcoal. I am, Dear Sir, yours most re- 
spectfully, 
Edinburgh, ) Will. H. Lizars. 
9jAst October 1822. j 
Art. IV . — Account of a New Escapement By Mr David 
'Whitelaw, Watchmaker, 16. Prince’s Street, Edinburgh. 
JL HE rewards which have been offered by Government, and 
the encouragement held out by the public, more particularly 
that part of it engaged in maritime enterprize, have called into 
action men of such talents within these last sixty years, that 
chronometers have been brought to a very high degree of per- 
fection. This has rendered it difficult now to effect any very 
decided improvement in their construction, though particular 
parts of them may still be susceptible of simplification. 
The escapements of Arnold and Earnshaw have been very 
generally approved of, and much used in the construction of 
both box and pocket chronometers. From a consideration of 
the small imperfections still belonging to these, which occurred 
to the inventor of this, in the course of his employment in the 
construction of chronometers, he found, that, by taking advan- 
tage of some well-known mechanical principles, improvements 
might still be effected in easing the balance, and diminishing the 
effects of friction in the escapement, by means of the following 
construction, in the description and investigation of the principles 
of which,' its advantages over that of Earnshaw will be pointed 
out. 
In this escapement, the teeth of the scape wheel may be 
those of the common detached ratchet kind, since a small part 
