424 Prof. Watuace on the Invention of the Pantograph, 
I had recourse to iron rods. These, however, it was difficult to 
get of the requisite straightness, while to connect them by joints 
convenient for motion seemed impossible. I consequently put 
them away, and betook me to rods of wood. 
« Placing one of these before my thoughts, I supposed it per- 
forated at certain distances, and hollowed out ; with this, so fitted 
for use, I found out something regarding the motion round the 
centre, but with regard to that to and JSrom the centre, it proved 
to little purpose. Next I joined two rods, using their common 
junction as a moving centre, and assuming a point, which might 
be in either, as a fixed centre ; but neither in this way did I at- 
tain my object. At length, making an attempt with four rods, 
forming a gnomon round a small parallelogram, I began to con- 
ceive better hopes of success. However, owing to placing the 
tracer and drawing pen almost always on the same rod, or in a 
position deviating beyond the straight line, I did not reach the 
desired end on the first day that I entered on the inquiry. The 
object of this invention related to the producing a copy broader 
than the original, but in what manner to perform corresponding- 
ly what referred to the height greatly perplexed me. TI had, 
indeed, learned how to go round the fixed centre, but I was un- 
certain as to the method either of receding from, or approaching 
to it. However, I did not despair, but after some consideration, 
I resumed the design of accomplishing the work at the hours and 
days of my leisure ; telling nothing to any one of my attempt, 
but sedulously commending it to God and my guardian genius. 
“These at last were not wanting to my arduous efforts, but 
most graciously imparted a knowledge of the whole secret, along 
with its scientific principles, on that same night which precedes 
the day sacred to Saints Fabian and Sebastian. In this reve- 
lation, the form itself of the instrument was so represented 
to my mind, its practice, and a demonstration of the whole 
shewn, as it were, at one glance, as if I had seen all things 
with my bodily eyes, and was receiving the lesson of a master 
