DEAR ST. NICHOLAS: I have often wanted to write to you before, to tell you how much I like your stories. In the July number of 1885, there was a story in which the training-ship "New Hampshire" was mentioned. I liked the story very much, because I can see the "New Hampshire" from my window. I am deeply interested in "Little Lord Fauntleroy," and I liked Miss Alcott's Spinning-wheel Stories very much. I hope to see my letter in print. Your constant reader, MAMIE S. W COLORADO. DEAR ST. NICHOLAS: I live on a ranch in Colorado and I look forward every month with great pleasure for the ST. NICHOLAS. I am going to tell you about a donkey we had once; we hitched him in a sled and tried to make him go, but he would not stir from home; after a little while we succeeded, and when we turned around he went like the wind, so that we could hardly hold him. The same afternoon he ran into a post and broke the sled to pieces. We have coyotes here, and they kill our sheep. One day I saw the herd running as fast as they could, and what do you think was after them? A horrid coyote, which was so thin that it looked as if it was going to die from hunger. The coyote is not a brave animal; it will sneak around and kill sheep, but it will never fight dogs. This is the first letter I have ever written to a magazine. Good-bye, dear ST. NICHOLAS. I am, ever your friend, IDA R. F. P. S.--I am eleven years old, and live eleven miles from a school. I have gained my education from reading ST. NICHOLAS, and studying at home. BUFFALO, N. Y. DEAR ST. NICHOLAS: In your February issue, there was a communication concerning "curve-pitching," and a diagram was used to explain why a ball curves in a certain direction. I beg leave to call attention to what I believe to be a mistake in the explanation. The writer says that the curve must be "toward the retarded side." I think it must be _from_ the retarded side; for, the ball while advancing is also revolving in a horizontal plane,--we will say from right to left. In its rapid flight, the ball condenses the air in front and tends to form a vacuum behind, and the condensed air in front attempts to flow around the sides of the ball to fill the vacuum behind. Now, in the diagram mentioned, the side B, the rotation of which conspires _with_ the motion of translation, resists, by friction, the attempt of the air to flow back; while the side D, in which the motion of rotation is opposite to the motion of translation, offers no resistance to the air in flowing around its side. For that reason the ball meets with most resistance in front of B, and least in front of D. Hence, taking the direction of least resistance, it curves toward D or _from_ the side of most resistance. Very respectfully, ELMER STORR. "THE FRANKLIN," WASHINGTON, D. C.