An Accmp of three Books ^ 
L A Difcourfe made before the R. Society, concemmg the Ufe of 
DUFLlCAt PROPORriONmfmdryimprtmt PmicuUrs; 
together vpith a New Hypthefts of ELJSll^ME or Springy Bo- 
dies : By Sir William Petty Knight^ c^c. 
^""W^HE Author of this Difcourfe, much addifled to apply 
Speculations to life and Prafiice, hath given in this Exercife 
of hiSy Several hjla^^cesywherei^ the Confideration of Dupliut and, 
Suh'duf UcM Prof ortion^or the Conjideration of Sides And their Squares 
fsofUje if$ liumm affairs. Thole Inftances are 5 
I .in the Dravoi/^g or Driving P Olivers ^^Yiich force Ships or other 
Bodies through the Water,with reference to the rcfpeftive Velocities 
caufed thereby. 
2. In th^ Shapes or Sharpnefs of Bodies i cutting or dividing the 
Water.through which they are driven or drawn^and in the difFerenc 
Velocities arifing from thence, where the Bodies andTorces are E» 
qua). 
3. Inih^ Strength of Timbers ^ or other Homogeneous materials 
applied to Buildings, to Carts, or any other Machinaments inten- 
ded for Strength : And how by a ^Model to judge the Sufficiency 
of fuch Engine as is reprefented by it. 
4. In the £j^^(?/0/^ri upon Equal and Like Veffels, according 
to their Numbers, Length, Blades, and Motions with or againjl the 
Stream of fmooch or un-even waters. 
5 . In the Motion or Iravelling of Horfes, on their feveral Paces^, 
and with different Burthens on them. 
6. In the Strength and Velocity of ^ills and their Wheels. 
7. IvithttStfksoi Gunpovpder. 
8. In the Diftance at which Somds may be heard. 
9. In the Diftances at whichOdoriferom matters may be fmelt, 
10. In the Diftance at which the Obje^s of Sight may be feen^ 
1 1. In the Time of the Returns made by Vibrating Penduls. 
1 2^ In the L,ives of Men and their Duration. 
13^ In M^^^/?/ and ^(J^^/i^^^/Wg Bodies, fuch as Strings and Bells- 
14, In the EfFefls and Motions of fir^*, and E/s^m;?^ 5]p/r/V/. 
1 5. In the Rifi^gaxid Falling of Bodies^ but efpecially of Water 
mPumps^ Over-fbot Mills ^ Leah \xi Ships, the Heights of Rivers 
at their Head above their fall into the Sea. 
In Bellows. 
17. In the Prices of feveral Commodities j as Mafts, Diamonds, 
large Timber, Amber, Load-ftones, c^c. 
