Patents, 
447 
stitution indeed interdicts them in criminal cases only ; but they 
are equally unjust in civil as in criminal cases : and the omission 
of a caution which would have been right, does not justify the do- 
ing what is wrong; nor ought it to be presumed, that the legisla- 
ture meant to use a phrase in an unjustifiable sense, if by any rules 
of construction it can be even strained to what is just. The law 
books abound with similar instances of the care the judges take of 
the public integrity. Laws moreover abridging the natural rights 
of the cidzen, should be restrained by rigorous constructions with- 
in their narrowest limits. 
Your letter, however, points to a much broader question, whe- 
ther what have received from Mr. Evans the new and the proper 
name of Elevators are of his invention : because, if they are notj 
his patent gives him no right to obstruct others in the use of what 
they possessed before. I assume it as a lemma, that it is the inven- 
tion of the machine itself which is to give a patent right, and not 
the application of it to any particular purpose of which it is suscep- 
tible. If one person invents a knife convenient for pointing our 
pens, another cannot have a patent right for the same knife to point 
our pencils. A compass was invented for navigating the sea ; 
another could not have a patent right for using it to survey land. 
A machine for threshing wheat has been invented in Scotland ; a 
second person cannot get a patent right for the same machine to 
thresh oats ; a third rye ; a fourth fieas ; a fifth clover^ &c. A string 
of buckets is invented and used for raising water, ore, &c. can a 
second have a patent right to the same machine for raising wheat, 
a third oats, a fourth rye, a fifth peas. See. ? The question then 
whether such a string of buckets was invented first by Oliver E vans, 
is a mere question of fact in mathematical history. Now turning 
tp such books only as I happen to possess, I find abundant proof that 
this simple machinery has been in use from time immemorial. 
Doctor Shaw, who visited Egypt and the Barbary coast, in the 
years 1727— =8, 9, in the margin of his map of Egypt, gives us thC 
jigure of what he calls a Persian wheel, which is a string of round 
cups, or buckets, hanging on a pully, over which they revolve,, 
bringing up water from a well, and delivering it into a trough 
above. He found this used at Cairo, in a well 264 feet deep, which 
the inhabitants believe to have been a work of the patriarch Joseph, 
Shaw’s Travels, 341, Oxford edition of 1738, in folio, and the Uni- 
versal History, I. 416, speaking of the manner of watering the 
high Iginds in Egypt, says—‘* Formerly they made use of Archi- 
