Patents* 435 
new, more Mmple, and effectual methods of using a well known 
principle, as in steam engine patents. 
But it should seem doubtful whether a new application of an 
old method or principle, ought to be a ground for a patent right, 
unless it obviously requires considerable skill in varying the applU 
cation. 
Thus, if a patent be granted for a new apparatus to distill 
aqua fortis, it would be absurd to grant another for its application 
to spirit of salt. If steam be applied to turn a cotton mill, it 
would be idle to grant another patent to one w^ho applied it to a 
grist mill. The owners of the Albion mills never attempted to 
take out a patent. Perhaps its application to moving vessels on 
water, or carriages on land, would require machinery so different, 
as to furnish some foundation for a patent right ; but in such case 
the specification and the claim, might include a description of the 
machinery used. 
There is a colliery about four miles from the town of Leeds., 
in Yorkshire, from whence there is an iron rail road to Leeds. 
A friend of mine, lately from England, informed me, that he had 
seen a steam engine in a waggon on that rail road, drawing after 
it twenty -two waggons^ each laden wdth three tons of coals ; in all 
66 tons. The wheels and the railway, were reciprocally cogged. 
They moved at the rate of four miles an hour. Granting this to 
be, as I believe it is not, the foundation of a patent right, would 
any body support another patent for driving coaches by steam? 
Hence it should appear very difficult to lay down any certain rule 
on the subject. In England, the jury aided by the court, might 
determine whether a patent contested on the ground of frivolity 
ought to be supported, under the head of its being of general in» 
convenience. That is, as it now appears to me, for I find no judi- 
cial determination hereon. In this country, the question is be- 
coming daily more interesting, where patents, frivolous, absurd, 
and fraudulent, threaten to become taxes on the community, in 
favour of persons, who may truly be said to raise money under 
false pretences. 
9thly. A patent may be granted for an invention or improve^ 
ment introducedfrom abr-: .cd ; for the benefit is the same to the 
public, whether the knowledge be obtained by travelling, or by 
studying. 
This is founded on the case in Salkeld, a very loose reporter. 
It may be fight in the infancy of the communication of knowledge ; 
