[ 123(^1 
fiBle at J, and only A, B,C zt E / or wherein 5, D, E, 
may be vifible at -^, and only C.F^A, at or where- 
in A may be of one lide of the quadrilateral, and £ 
on the other; or one of the ftations within the quadri- 
lateral, and the other without it: I (hall for brevitys 
fake omit the figures, and diverlity of the Signs 4 and — 
in the calculation, and prefume that the Surveyour wil 
ealily dired himfelf in thofe cafes, by what has been faid. 
The Solution of this third problem is general, and 
ferves alio for both the precedent. For fuppofe C, D 
the same point in the laft figure, and it gives the folu- 
tion of the fecond problem : but if 5, f, be fuppos'd the 
lame points with D, F, by proceeding as in the laft, you 
may dirc&ly folvc the firft problem. 
A Letter from William Molyneux Efq ; to one of 
the Secretarys of the R. S. concerning the Cir- 
culation of the blood as feen^ by the help of a 
Micro/cope^ in the Laceita Aquatica. 
Duhlm OM. 27. i685r. 
iS'/r, 
OUR Society lately received tmnfcripts of two 
of D' Gardens Letters, the firft dated form A- 
ierdeen ]\i\y 17. K^Sy.to D' Middleton; the other Sept. 
4. 16% y. to D' Plot. To both thefe Letters I have 
fomething to fay. 
In the firft he gives an Account of the Vifible Circula- 
tion of the blood in the Water-Newt or LacertaAquaticai 
truely I am heartily glad, that this Learned and Inge- 
nious D' has hit upon this Experiment; tis now above 
two years and an half, fincelfirft Difcovered this fur- 
prifing 
