( 5151 ) 
in that tedious train of divers operations that are to be 
lusde ia foHowing the common methodj generally taketh ^ 
away the pleafure that would be in the exerciie of a work , 
thatelfeisfo curious and ufeful 5 is of opinion, that thofe 
loventions will be much efteera'd , that iliall make this- 
p'raftife eafie. And in order thereto^ he defcrlbes and ex« 
plains in this Tradt iv^o Engines^ which to him fee very 
proper for that purpofe vforaimuch as he finds,that by the 
means of tliem a man coaylearHin lefs than an hour 
way of making all forts of Byals^ aod may prad:ire what he 
has IearDt,as 'twere by playing, drawing them upon W^lis 
andinhis Ghamber with the greateft facility. 
He addsjthat we are not to imagine^that the Ufe of theft 
Iflftruments is butfuch a Mechanical Operation^ where a 
raao works blind-fold^not knowing what he doth : And he 
declares^ that^as loOpration^xkioi^ Pradiles that are fim- 
pleft ax>d (ureft are to be held the beft and the moft geo-- 
metrical 5 and he is of opinionjthat fcaree any thing can be 
done with Icfs trouble or with more certainty than by 
means of thefe Machines. But then, if the queftionbe, to 
learn thcTheory otDyallinf^, he believes not^ that it can be 
better done than by the life of thele very Engius 5 wherein 
he affirms that the Learner may eafily be made to under^ 
ftand the Reafon of all the Operations^the Refpeft of the 
Horary lines to the Courfe of the SuOj the Sedions which 
ij the Arches of the Signs do makejand^in a word, the whole 
Science Gnomonique. 
The Defcription and Explication of thefe Inftroments 
doth fo much depend upon the view of the Schepies, em- 
ployed thereiojthat it cannot be well made without them 
Which maketh os refer the Curious Reader to the Tr'aA it 
ielfjuow come over^ wherein the neceflarj Schemes art an- 
nexed to the Difcourfe* 
