IN a paper read before the Royal Society of Arts Ion March 17 on "The Displacement of Labour by Machinery" and recently made available, Mr. H. D. H Henderson discussed the subject of the effect of technical progress on employment. The contention invention is now flowing in a direction which merely leads to the introduction of machinery so automatic that scarcely any labour is needed to operate was described as plausible but devoid of substance. The distinction, on which it rests, "between mechanization which is in the main co-operative with labour and that which is in the main competitive with it is illusory, since all mechanization diminishes the amount of labour employed per unit of output, while the inventions which have done most in the past to stimulate economic activity have entailed an especially large economy in this respect, believes that the old economic argument, which sought to prove that technical progress serves in the long run to expand rather than to contract the demand for labour, is still valid. Owing to change in population trends, however, the process of technical development is likely to be accompanied in the future by greater difficulties and more awkward problems of adjustment. These problems cannot be escaped by slowing down the rate of technical progress, so far as this depends on the extended use of machinery. Such action would only intensify our difficulties while depriving us of the benefits of mechanical advance.