The term Progress in Science the meaning which is most simple and direct, suppose it refers to the growth of knowledge of the world in which people live. The progress of the physical and chemical sciences in recent year's people observes that a few great generalizations have been of extraordinary importance. The purpose of scientific enquiry is to add to the extent and the accuracy of that knowledge. The methods are based on observation: people are content to watch what Nature does, to examine the materials which she uses, and to trace relations between her various operations. The success depends upon the accuracy with which people can observe, and upon the number of comparisons which they can make. To many of us it is a continual pleasure to make these enquiries. There is the incentive that they are often difficult and baffling, sometimes yielding rich and unexpected results, more often giving no more enjoyment than that of the unsuccessful chase.