and Description of the Eidograph. 427 
of my parallelogram ; for both publicly in school did I deliver to 
my pupils precepts in the art of delineating objects on a plane, 
along with sound demonstrations, and at home also, privately, I 
revealed to many the abstruser doctrines of the science. By 
this means it happened that a general knowledge of the art got 
abroad. I made, however, a more free communication to those 
who were going into the Spains, and thence about to traverse 
the eastern and western worlds for the dissemination of the Ca- 
tholic faith, that they might have by this means a more ready 
access to conciliate the benevolence of mankind, and thence in- 
stil more easily truths of deeper moment into minds thus pre- 
pared to receive them.”* 
The Pantograph has no defect in its geometrical principles, 
but, considered as an instrument for practice, it is by no means 
perfect. It is composed of metallic bars, which turn on five 
centres ; it is supported on six rollers turning also on centres, 
and continually changing their direction while they move along 
the paper; and when the instrument is used, the force which 
changes its figure is in some positions applied obliquely, and 
thus acts at a disadvantage. On all these accounts, its excellence 
as a working machine is by no means equal to the perfection of 
its geometrical theory. Land-surveyors sometimes use it from 
necessity, in reducing or enlarging plans, but the engraver hard- 
ly ever employs it ; indeed, in his more delicate work, he can de- 
rive from it very little assistance. 
In the summer of the year 1821, my attention was directed 
to copying instruments. I found that the Pantograph was then 
the only one used; and I formed the resolution of attempting to 
invent a new instrument, which should be free from its imper- 
fections. ; 
* The remainder of Scuzi1neEr’s first chapter contains nothing now particularly 
interesting ; it is therefore needless to continue the extract: farther. 
VOL. XIII. PART II, 31 
