234 Memoir of the Life of Ely Whitney. 
dence given in support of It, establishes a presumption, that he must 
have derived the plan of his machine from a similar one used in the 
cotton manufactories in Great Britain. 
In support of the second ground of defence, evidence was pro- 
duced to show that Mr. Whitney now uses, and that the defendant 
also uses, teeth, formed of circular iron plates, instead of teeth made 
of wire. And it was contended that this is a departure from the 
specification, and an improvement on the original discovery, which 
destroys the merit of that discovery, and the validity of plaintifl’s 
patent. It was also insisted that the plaintiff had concealed the best 
means of producing the effect contemplated. 
r. Noel of counsel for the plaintiff, in opposition to the first 
ground of defence, stated two points—First : ‘That if the principle 
be the same, yet the plaintiff’s application of that principle being new, 
and for a distinct purpose, has all the merit of an original invention. 
Second : That the principle of Mr. Whitney’s machine is entirely 
different from that exhibited by defendant. 
e defined the term principle, as applied to mechanic arts, (© 
mean the elements and rudiments of those arts, or in other words, 
the first ground and rule for them. That for a mere principle, ¢ 
patent cannot be obtained. That neither the elements, nor the man- 
ner of combining them, nor even the effect produced, can be the 
subject of a patent, and that it can only be obtained for the applic®- 
tion of this effect to some new and useful purpose. 
To prove this position, several examples were stated of important 
inventions, for which patents had been obtained, which had resulted 
from principles previously in common use, and an argumen 
celebrated Judge, at Westminster Hall, was cited, in which it is 
serted “that two thirds, or three fourths of all patents granted since 
the statute passed, are for methods of operating and manufacturinss 
producing no new substances, and employing no new machinery $ 
and he adds, in the significant words of Lord Mansfield, va patent 
must be for method, detached from all physical existence whatever 
The second point was principally relied on, to wit: That the pm 
ciple of Mr. Whitney’s machine is distinct from that produced by 
* defendant, and new in its origin. 
- t consists of teeth, or sharp metallic points, of a particular it? 
ape, and its application is to separate cotton from the see" 
s the principle of the model exhibited by the defendan 
of every other machine before invented, and used for the same 
