8 
cent, has been considered a fair royalty in some cases, while 
in others three per cent, has been awarded, but when a fixed 
amount has been stated the sum has worked out in terms of the 
full price of the machine as low as two and a half per cent, in 
exceptional cases. 
The licence granted is usually not an exclusive one, nor is 
it always for a fixed period, but it is unlikely that any other 
person would be granted a licence if the original licensee 
actually carries out the invention and does not hold the 
licence as a negotiating instrument or as a means solely to 
prevent any other person from using the invention for the 
public interest. 
The Board of Trade may revoke the licence if they are of 
opinion that such was obtained by misrepresentation, whether 
intentional or not, or that material facts were not made 
known at the time of the grant. 
The licence may also be revoked by the Board of Trade 
upon the application of the licensee should the patentee or 
owner of the patent have offered him another definite licence 
upon terms considered reasonable by the Board of Trade. 
The term for which the licence is granted by the Board of 
of Trade when suspending a patent in favour of a licensee is 
stated to be “ for and during the period not exceeding the 
unexpired residue of the term of the said Letters Patent 
during which the Suspension Order shall be ixu force,” but it 
is extremely improbable that a second licence will be granted 
to any person while one suspension licence exists, unless it 
could be shown that the original licensee had failed to satisfy 
the reasonable requirements of the public w r ith regard to the 
patented invention, or that unreasonable and excessive prices 
had been charged for the articles made under licence. 
Records to be Kept. 
The licensee is required to keep books in which particulars 
are recorded of all articles sold, particulars also of all patent 
articles made for the licensee by others, and particulars of 
all such articles sold, prices charged for them, their actual cost 
of manufacture, and prices paid for them by the licensee if 
any other person has manufactured them to his order.