G.— ENGINEERING. 135 



culties which he had not foreseen, and the remedy for which may not be 

 patentable. Such obstacles and tbeir remedy cannot be recorded in the 

 patent because they have not been encountered when the specification 

 is written. If it be argued that the inventor should not apply for a patent 

 until the practical application of the invention has been achieved, then 

 the inventor argues in reply that by delaying his application he is incurring 

 the risk of having someone else forestall him, by fair means or foul, and 

 so lose his trade monopoly. Under our present system a period of nine 

 months is allowed between filing the provisional and complete specifica- 

 tions, which period, while ample in the case of most inventions, is inade- 

 quate for full investigation of the really great inventions, and it is to this 

 difference between major and minor inventions that I wish to draw 

 attention. 



In America it is possible for an applicant for a patent, by filing periodical 

 amendments of his specification, to keep the application pending in the 

 Patent Office for a number of years, during which he can be developing 

 the invention and adding to the specification any further explanations 

 which may be called for in the light of the experience gained. Then when 

 the patent is eventually issued it runs for seventeen years from the date 

 of issue, whereas a British patent dates from the date of application. 

 In addition to this, an American patentee, on any question of priority of 

 invention, is allowed to produce any evidence that may be available to 

 show conception of the invention up to not more than two years anterior 

 to the date of his original application. In this way an American inventor 

 can spend several useful years perfecting his invention before his patent 

 is granted, while the British inventor has often to watch the most useful 

 years of his patent being eaten up in unproductive development. I 

 admit that the American system has drawbacks from the point of view of 

 an industry, but it has certain undoubted advantages, and I suggest that 

 our system does not meet the needs of great inventions, between which 

 and the ordinary minor inventions there ought in my opinion to be some 

 discrimination. Merely as a suggestion, I see a possible solution in an 

 extension of our present system of granting Patents of Addition, that is 

 a patent for an improvement on a prior patented invention, the Patent 

 of Addition being granted during the lifetime of the original patent and 

 running coterminously. If a Patent of Addition could be granted to an 

 inventor in approved cases on production of evidence of genuine diffi- 

 culties encountered and successfully overcome, these difficulties and their 

 remedy to be fully described in the patent for the guidance of the industry, 

 and if this Patent of Addition could be made valid for a definite term of 

 years, one of the main fears of a patentee would be overcome. 



It will be noticed that in this last suggestion I have stipulated that 

 the specification of a Patent of Addition such as I suggest should contain 

 not only a description of the finished invention but of all the difficulties 

 encountered in its production and the steps taken to surmount them. In 

 fact, it is mainly for this reason that I make the suggestion at all. I am 

 trying to devise a means to prevent future inventors and industry from 

 being handicapped in a way that has been all too common in the past. 

 I have already touched on what must be the large volume of valuable 

 scientific information that has been lost through lack of records of past 



