The CONTENTS. 
:V. An Experiment to [hem that the Friction of 
the federal Tarts in a Compound Engine, 
may he reduced to Calculation j by drawing Con- 
ferences from fome of the Experiments , fhewn 
before the Royal Society lajl Tear , upon 
Jimple Machines, in Various Circumftances, by 
me. Now exemplified ly the Friction in a Com- 
bination of Pullies. 'Ey the TeV d - J. T. De- 
faguliers, LL T>. F. <%. S. Jan. 14, 1731. 
O'- . O '*1 O' rr; frO r 1 7 . ,, f . , f .. 
s . ~ “ " 4 '*/ - - ' v ~* . Vj J'li \ x j\ I 
!VI. An AbfiraEl of a Letter, written in Dutch, 
to the llluftrious Royal Society of London, 
by Arnold Marcel, ( Nephew to the late 
Mr. Anthony van Leeuwenhoek, F. S .) 
Communicated by the t^ev dw Dr. J. T. Defagu* 
liers, F. <R. S. 
' ' ' 
\ v. ' / * w n v? * r , * t i % 
' -(.■• Ai- -Arc. ,<a-- O - ■ . 
L 0 NT> 0 N : 
Printed for W. Inn vs, at the Weft. End of St. 
^Paul’s Church-Tard. 
MDCCXXXII. 
