( »88 ) 
^A LetUr M^John Gonyers, Citize^ofLotidcm ; the Authr 
cf the Hygrofcope defcribed Numb. 129 ; in vpbich Letter 
is contained a Draught and Defcripicn of a very ufefuland 
cheap Pump , contrived hy the fatd Mr, Conyers ; a Trial of 
which rvas alfomade at the Repairing cf the Ner^ Canal of 
Fleet-river in London, and elfettfhere. 
SIR, 
I Have here inclofed a Draugjic of a very ufeful and cheap 
Pump, v/l3ich aboat the Year 1673 was by mecontrived, 
and by my direftion ufed and made at the Kew Canal of FJeec- 
river in London at the Work there, v^hen the River wzs lately 
enlarged as now it is 5 and this Punip v. as then found to empty 
and raife at leaft twice as much Water proportionably as thofe 
of the fame or rather bigger bore, that were firftmade ufeof 
and caft by ; for, being Taper or Conical ail the way, and 
thfe Cylindrical , thi^ would raife and caft out twice as 
much Water at leaft at one ftroke, as the other Cylindrical 
ones would do with the fame bore and flrength. Now you may 
difcern by the fafiiion, that , as there is no Brafs or Lead work 
here, fo it will be purchafed at a cheaper rate than ufual ; and 
as there is liberty in the motion, fo there will be no wearing 
or rubbing upon the fides of the Bucket: Befides this, you 
may with the fame eafe by which you caft out of a cylindri- 
cal bqre, caft out twice as much at leaft out of this : So that 
how ufeful this may prove for drainingof Low grounds, Pitts, 
Mines, Fifli ponds, and for Shipping, Time and Experience 
muft difcover. This Engin was then recommended by Dr. 
Francis GliJfon. zsdiWo hy Dr, Jonathan Goddard to the Royal 
Society^ whilft it was ufed in the Canal abovefaid. 
Now this being the largeft yet made about nine foot in 
length, and the fmallcr end or bottom-bore eight inches , and 
the top one foot eight inches bore , it was found to caft out at 
leaft eight Gallons at one ftroke - and this was a Bore of a fqua- 
red faftiion, being made of Planks nailed together, and Iron- 
hoops added to ftrengthen it on theoutfide; which alfo in 
proportion may be made to what length or breadth you pleafe» 
Now, though the Bore be large at the top, there is no more 
weight of water that lies oa the bore at bottom , than juft the 
breadth there ; the reft is born up by the fides, and the fmpulfe 
dCWater by that means. is rmde in the water with out grating a- 
gainlt 
