In an appendix I set out the story as it has been given me by Sir Daniel Hall. It is rather technical, but may be summed up simply. Pascal received both attempts at solutions and replies which merely discussed germane matters. Wren sent a partial but admirable contribution, unfortunately “without demonstration.” It was original as far as it went, but not the complete solution for which Pascal had asked. Cavarci, the umpire in this high contest, wrote that Wren had merely solved the easy part of it. It appears clear that in withholding the prize Pascal wronged neither Wren nor the other contestants. The suggestion that Wren was the master mathematician of Europe will not do. It is enough to affirm of him that he was an ingenious geometrician who made several minor advances in that science. He left no evidence of mathematical _genius_, a quality which ought to be reserved to the authors of far-reaching and fruitful conceptions. The true significance of Wren’s mathematics lies in the fine way in which he applied them in his buildings. No one is a better representative of applied science as compared with pure or fundamental science. Too much has also been made of Wren’s work on the barometer. Some enthusiasts have, indeed, tried to transfer to him the credit which belongs to Torricelli and Pascal. Wren repeated Torricelli’s experiment at the top and bottom of a hill, and finding that the mercury column stood at a lower height on the top of the hill, argued that the mercury was really balanced by the weight of the air, or, as we now say, measured its pressure. But in this experiment Wren was anticipated by Pascal; his experiment was regarded by his contemporaries as made independently, but it would be hard to say that the experiment was really Wren’s own device, so much was the question a matter of discussion among the men of science of the time. The enunciation of the laws of impact was made practically simultaneously by Wallis, Wren, and Huygens. Wren’s may be regarded as the most elegant demonstration, but it was Huygens alone who perceived that when the colliding bodies are perfectly elastic the energy of the system, _i.e._, the sum of the products of the mass of each of the bodies multiplied by the square of its velocity, remains unchanged--one of the generalisations at the base of modern science. Similarly, although Wren became Professor of Astronomy both at Gresham College and then at Oxford, no outstanding observation or fundamental discovery remains attached to his name. Speaking broadly and generally we can say that Wren was universally accomplished in all the science of the time, that in several directions he showed a quality of mind that was only short of the highest, and that finally he abandoned the pursuit of pure science too soon to have accomplished in any branch such a mass of work as would mark him as one of the founders of that science. It must always be remembered that Wren took to architecture when he