VIII. Extract of a Letter from Monf r de 
L'lfle to Mr. Nettleton, containing the 
affinal Menfuration of the Bafis propofed 
p. 42 . Eranflated from the French by 
T. S. M. D. F. R. S. 
Tetersbourg , May 14, 1737. 
SIR , 
* * * ^ I N C E my laft to you, I undertook to 
meafure the Bafis which I fpeak of in Page 
42 of this TranfaElion , and had the good Fortune to 
meafure very exadly on the Ice, by taking the precife 
Diftance between her Imperial Majefty's Caftle o&Re- 
terhoff \ and the Caftle of Doubkiy fituate oppofite to 
it, on the Coaft of Finland . I found the Diftance 
between the oppofite Walls of thefe Caftles to be 
74,250 Feet Englijh- . This Bafis, being much greater 
than any of thofe employ'd hitherto for this Purpofe, 
gives room to exped great Exadnefs in the whole 
Work, when it fhall be carried on in the fame Man- 
ner. It will at once ferve to make a very exad Map 
of the Bottom of the Gulph of Finland. Tis for 
the fame Defign, and for better ordering the Charts 
of the Coafts of the Balticky that I intend (as foon 
as my Projed fhall be approved here in its full Ex- 
tent) to begin to meafure my Triangles along the 
Coafts of Ingria and Livonia , to the Iflands of 
Daghoy Oefely &c. And to the end that the Charts 
of the Places taken in by thefe Triangles may be 
ftniftf d at the fame time, I fhall take with nae all the 
Charts 
