growth of truth, which you call scientific truth? If these beliefs are destroyed, is it not a conclusive proof that they may be false, or at least contain an element of untruth? The religion may, indeed, have been very useful, although not true, and not qualified to satisfy all the aspirations of a cultivated mind. You may see, when a civilized race comes in contact with a lower race, that the effect of the sudden contact may be to destroy the religion and the rule of life of the inferior race, without putting anything in its place. Evils of that kind have been caused by modern science. It is destroying inevitably many beliefs which people have lived under well and happily. It is undeniable that this causes pain, and that it may be injurious to their morality I shall not attempt to deny. But when I am asked to say that therefore science is injurious, I have to come back to my original proposition—the remedy is more science. The only way out of the difficulty is this: we are here, and we have got to go—forward. And the only way is, to apply the test of truth to all our beliefs. This effects a certain amount of pain, as every other kind of progress does; but the only other way is to go on believing what you know to be lies. And, without saying which are true and which are false, I can not see who any person can wish to do anything else but increase the amount of truth, the only satisfactory cure."—Knowledge.
TO render easier of attainment instruments which assist in the investigation or contemplation of natural phenomena, and which supplement man's sense-organs, is to forward by so much the diffusion of real knowledge, and to aid the work of human enlightenment and progress. Indeed, it is not to be doubted that the popularizing of instrumental aids for experimentally verifying the teachings of scientific discoverers will form a notable part of the work of the future schoolmaster.
A few years ago I derived great pleasure from successfully constructing a home-made microscope, guided by directions contained in "The Popular Science Monthly," at a time when my means did not enable me to purchase a good instrument from the optician. I now lay before my fellow-readers the following directions which, step by step, I myself have put in practice, in making a really serviceable achromatic telescope, which will exhibit the moon's surface magnificently, and show very satisfactorily the spots on the sun's disk, the satellites of Jupiter, and other celestial phenomena.
Some people conclude that, if they can not possess a first-class in-