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A Catalogue of 
Mathematical inftruments are the means by 
which thole noble fciences, geometry, philofophy, 
aftronomy and opticks, are rendered ufeful in all 
the common and neceffary occurrences of human 
life. By their afftftance an abftradled and unpro¬ 
fitable [peculation, is made beneficial in a thoufand 
inftances: in a word, they not only enable us to 
connect theory with practice, but alfo inftruff us 
how to turn bare contemplation, into the moft 
fubftantial ufe, by making one of the moft fervice- 
able branches of learning, the natural way of ren¬ 
dering this knowledge general and diffufive. 
The knowledge of thefe leads to that of prac¬ 
tical mathematicks, and experimental philofophy ; 
fo that the ufes of mathematical and philofophical 
inftruments, make perhaps one of the moft fer- 
viceable branches of learning in the whole world ; 
and the natural way, therefore, of rendering this 
knowledge general and diffufive, is by making 
that of its inftruments fo. 
A s practical mathematicks, and experimental 
philofophy, teach us the powers of nature, the 
properties of natural bodies, and their mutual ac¬ 
tions on one another ^ this knowledge cannot be 
attained without inftruments, and the conclufions 
and proofs we expecl from it, depend very much 
upon their exadfncfs. In order therefore to give a 
fufficient fatisfadlion to thofe who honour me with 
their cuftom, it is my particular and greateft aim 
to produce fuch inftruments as may facilitate the 
progrefs of mathematical and philofophical learn¬ 
ing. 
In all my performances I endeavour not to aug¬ 
ment the inftruments with fuperfluoiis ornaments, 
that they may be of frequent ufe to thole of mid¬ 
dling fortunes, and alfo that their neatnefs may 
render 
