Few of his later and larger achievements in this field could be fairly regarded as works of necessity, strictly speaking; they rather were meant to be aids in the great enterprise of evangelizing the Chinese Empire. He was thoroughly convinced that one of the most powerful agencies that could be employed for this purpose was the school and the college. He was equally sure that of all the studies that could be introduced into the curricula of these institutions, none could be so effective in opening the way for the gospel as that of the natural sciences, and especially physics, inclusive of modern mechanical appliances of its principles. He believed that if bright young men were educated in that kind of knowledge, and sent out under Christian influences among their own people, if they were also converted to Christianity, the outcome must be the dissipation of the existing blind adherence to the superstitions and ideas of centuries long remote in the past; and that with this must come the opening wide of the door for the entrance of Christianity. That was his forecast; and the present situation in China goes far toward vindicating the wisdom of it. But to teach effectively the natural sciences he must have apparatus. The only way he could secure this was by buying what he could, and by utilizing his own ability to set this up, and to add as much as possible for the outfit yet needed. Such was the prime object not only of what in a more limited sense constituted the apparatus of the school and college, but also of such larger appliances as the plant for heating and lighting the premises. These were far more than conveniences that helped to better work; they were themselves constant exhibitions to the students and to the people at large of the principles of natural science, and of their value in the affairs of actual life. Dr. Mateer utilized his outfit of apparatus and machinery as a means of reaching others besides the students in his own institution, with the influence of modern science, thus opening a way into their minds for the gospel. As to one of his methods of accomplishing this object Ada gives a graphic account: