C 216 ] 
the knowledge of which is of great importance to 
one who would fuccecd in an undertaking of this 
nature. Olcarius never flirred out of 'his {hip: and 
the map contained in the Ruffian Atlas, is fo fliame- 
fully deficient and faulty, that the academy very 
readily acknowledged the improvements made by 
my map, and thankfully accepted of it, although 
no life was made of it. During my flay at London, 
in 1766, I made a revifion of my papers, cal- 
culated again all diflances and angles, and corre&ed 
my map in more than twenty places, lb that this may 
be juflly called a new and improved one. 
The canal made by Perry, in the year 1697-1701, 
for the conjundlion of the Volga and Don, I fur- 
veyed j and conftrudted a fpecial map of it, of more 
than three yards fize, and can therefore anfwer for 
its accuracy. The canal begun by the Turks, no- 
body ever took notice of befides me in a map ; which 
I did, from an account I got, by means of Mr. 
Reufs, and fome others, and from a rough fketch of 
it, communicated to me. That part of the Don, 
which appears in the map, is taken from the very 
accurate and famous map made by the vice-admiral 
Cornelius Cruys, and publifhed in fourteen fheets in 
.Holland. 
This, I hope, will fatisfy the public in refpeift to the 
accuracy of the performance, and enable the Society 
to judge better, whether it deferves to be publifhed 
-or not. I am, with the greatefl refpebt, 
S I R, 
Your mofl obliged and humble fervant, 
John Reinhold Forfter. 
XXXIV. An 
