"The writer of this note is a clergyman who became tremendously interested in telescope building through your book for amateurs on the subject. My reflector is four inches in aperture, with a focal length of 34 inches and it cost me only $3.45, exclusive of the eye pieces.

"I procured two disks of glass, four inches in diameter, half-inch thick, for 60 cents with ground edges, from a Newark plate glass company. The rouge, carbo, chemicals and so on, made up the rest. Great attention was paid to the fine grinding. Flour emery was used until I was 'blue in the face' but it paid handsomely when it came to the polishing. The radius of the curve was 72 inches but it shortened to 68 inches during the polishing. I will never forget

those shadow tests. The first series showed I had a regular well dug in the center of the mirror, so I cut out the center of the tool and soon had a sphere. I used a goodly proportion of beeswax in the pitch lap. The final parabolizing was done in a total of about ten minutes of actual work, but it involved nearly a whole night of waiting and testing-I'll never forget that 'session.'

"A taxi smashed up on our corner, so a piece of its windshield formed the diagonal. The silvering, according to your instructions, went very easily-except, I may add, that I silvered everything in sight.

"The mirror was set in the cover of a coffee can. This was bolted by long screws to the back of an old radio dial. I used this because this type has three rather heavy springs. The whole thing adjusts like a million dollars. This assembly was fixed to the end of the tube with three brass clamps. The tube was stove pipe (20 cents) with a band of heavy galvanized iron on each end.

"The mounting is crude plumber's fittings. A floor flange was bolted to the tube and a piece of half-inch pipe was screwed into it for a declination axis. The latter was inserted in a "T' which was drilled for set screws and lined with sheet copper to take up the play. The fitting for the eyepiece was a problem until an old drain fitting was found, providing the flange and tube. The finder is a small one dollar telescope but it doesn't work half as well as simply sighting along the tube as one would aim a gun. Later, I replaced the diagonal mirror with a one-inch prism and the result is more than worth the cost. I am using ordinary microscope eyepieces.

"I love to view God's heavens through my reflector. It is a 'grand and glorious feeling' to see Jupiter and her moons and the other wonders with an instrument I have made with my hands."

The small dollar telescopes mentioned by the Reverend Mr. Cutler are of little use as a finder because they are of the old Galilean variety, easily recognizable by the outside of the eye lens which is concave. The field of view of a Galilean telescope is limited to about a degree in diameter while a finder should take in three to five degrees. However, no finder is needed; a simple homemade gunsight with a ring is virtually as satisfactory; or simply aim the tube, as described above.

From another clergyman, Rev. Edwin H. Smith, pastor of the Epworth Methodist Church, 1270 Sanchez Street San Francisco, California, comes another ;inspiring communication. "It was my good fortune, about a year ago," he writes, "to learn of the book of instructions, 'Amateur Telescope Making.' The proposition seemed to me altogether incredible, and I think that I would not have attempted the making of such a telescope, had it not come from the SCIENTIFIC AMERICAN.

"I first made a six-inch mirror, and succeeded so well that I proceeded at once to make a ten inch. And now I am simply amazed at three things-the small cost in money; the marvelous powers and perfection of the mirror; and, most of all, the fact that I made it with my own hands. Every once in a while J have to go out and turn the telescope on the moon, or something, in order to satisfy myself that it is not all a dream. And when someone comes along and questions the cost of materials, only 20 dollars, I can't feel sure of that either, until I go over the bills and check them up again.

"It was my very great pleasure to take the ten-inch telescope up to Camp McCoy, a Y. M. C. A. summer camp for boys in the Sierra Nevada Mountains. There, at an elevation of. 6000 feet, and in the transparent atmosphere of the mountains, the definition, at the power of 170 diameters, was clear, sharp, wonderful, amazing. Another very interesting experience was a visit to the Lick Observatory on Mount Hamilton where one thought troubled me. We were to see the planet Saturn through the big 36-ineh refractor and I was wondering whether I should have any respect for my little reflector? after looking at Saturn through that big refractor. Well, good fortune or bad, the night was not the best for 'seeing.' The atmosphere was 'boiling.' So the view of Saturn was not quite clear and only three of the satellites were visible. The result was that I came down the mountain prouder than ever of my little ten-inch telescope."

In addition to the two clergymen whose interesting letters appear above, it is known that several others are at least interested in telescope making, for copies of A. T. M. have been obtained by them.

One rather interesting aspect of amateur telescope making has been the women who have taken it up. Can a woman make a telescope? Well, why not? In the original group of amateurs at Springfield, Vermont, led and instructed in 1921 by Russell W. Porter, there was a woman who made a good mirror. There have also been a number of women purchasers of A. T. M. Here in New York two of these seem to be making out very well, both having brought in their mirrors for our admiration. One took her mirror to "Stellafane" and finished it there.

Mr. Porter reported: "Mrs. W. finished her mirror last night, a very good mirror; the first woman I know of who thoroughly understands the knife-edge test, among amateurs." Doubtless the last two words in his statement refer to the fact that a woman telescope maker was for some years employed professionally at the famous Brashear shops in Pittsburgh. It is hoped that those of the amateurs who are not already peeved because women have recently invaded the trades and professions and ruined the sacred clubbiness of our barber shops, will throw down the challenge to their wives, sisters and others to make a mirror. We would like, say a year hence, to devote the whole Back Yard of one issue to telescopes made by women- they, of course, to appear in the pictures for art's sake.-A. G. I., Tel. Ed.

The Society for Amateur Scientists (SAS) is a nonprofit research and educational organization dedicated to helping people enrich their lives by following their passion to take part in scientific adventures of all kinds.