THE externals of modern civilization are the products of invention, and a scientific analysis of invention, what it is, what causes it and whither it is leading us, is long overdue in England. In such an analysis the statistical method must predominate and the easy generalization will have no place. It may require research of a difficult and unusual kind, but unless we know, for example, accurately and in detail, the origins, the training and the methods of successful present-day inventors, we do not know the sources of the real progress-making inventions of to-day, and while we are ignorant of that vital fact the recital of a short list of so-called working-man inventors of the eighteenth century is not merely valueless but also misleading. Mr. C. W. Marshall has just concluded in the Inventor a series of articles on “The Science of Invention”. In them he attempts to interest and guide inventors of various degrees of proficiency, but, although the trend of recent patent applications can be learned from them, the articles are entirely devoid of statistics. As a consequence of this and of the very diverse standards of the inventors to whom the articles are addressed, their total effect is confusion. At one place advice is being given as to the “psychological factor”; for example, “a camera idea, may be submitted to manufacturers in the autumn so as to be ready for the spring sales”. Shortly after this we learn or do we? that the “price of inventions used to vary from £1,000 for ‘gadgets' to half a million for inventions such as refrigeration and automatic photo machines”. Again, “There is a ready market for inventions which cheapen production of exclusive products. By introducing mass-production machines and an entirely re-designed, simplified product the early Fords were able to tap the potentially great motor-buying public”.