INTRODUCTION® Vll 
practice to the circumstances in which they 
may be placed. 
Such is the nature and purport of the 
present work, and I have only to add that 
I have spared no pains to render it as 
perfect as I could make it. The engravings 
have been made here from drawings of 
specimens previously prepared, and I can 
therefore vouch for their accuracy. 
J. W. L. 
Bayswater, May 21, 1840. 
