( 5I5I ) 
in tBat tedious train of divers operations that are to be 
made ia followlDg the common method, generally taketh 
away the pleafure that would be in the exCrcife of a work 
that eife is fo curious and ufeful 5 is of opinion^thatthofe 
luventions will be much efteem'd , that lliall make this 
praftife eafie. And in order thereto, he defcribes and ex. 
plains in this Tra^t two Engines, which to him feem very , 
proper for^that purpofe 3 forafmuch as he finds,that by the 
means of them a man may leara in lefs than an hour the 
way of making all forts of Dyalx, aad may pradife what he, 
has learDt,as 'twere by playing, drawing them upon Walls 
and in his Chamber with thegreateft facility. 
He addsjthat we are not to iniagine.that the Ufe of thefs 
Inftrumentsis but fuch a Mechanical Operation, where a 
man works blind-fold,uot knowing what he doth : And he 
declares, that,as to Operation, thofe Pra^iifes that are fim- 
pleft ai>d fureft are to be held the beft and the moft geo-- 
metrical j and he is of opiD!on,that fcarce any thing can be 
done with lefs trouble or with more certainty than by 
means of thefe Machines. But then, if the queftion be, £0 . 
learn theTheory of Dy ailing, he believes not, that it can be 
better done than by the Ufe of thefe very Engins 5 wherein 
he affirms that the Learner may eafily be made to under»< 
ftand the Reafon of all the Operatious,the aefpeft of the 
Horary lines to the Courfc of the Sun, the Seftions which , 
the Arches of the Signs do make,and, in a word, the whole 
Science Gnomonique, 
TheDefcription and Explication of thefe Inftrumcnts 
doth fo much depend upon the yiew of the Schemes, em-- 
ployed therein,that it cannot be well made without them .» 
Which maketbus refer the Curious Reader to the Traft it 
felfjDGW come over,d[iereio the neceffary Schemes are an- 
nexed to the Difcourfe, . 
i 
