CONSTANT READER.--1. All the foremost juvenile writers of the day are engaged on GOLDEN DAYS; therefore, in our opinion, there are none better or more popular. 2. The various officers in the United States navy rank as follows: Rear admirals, commodores, captains, commanders, lieutenant commanders, lieutenants (two grades), ensigns (two grades), and naval cadets. Rear Admiral Walker is the head of that branch of the service at the present time. 3. They were published in a magazine bearing his name. 4. See the naval pay-table in the Letter Box of No. 15, Vol. 12. A JAY.--1. Martin, the winner of the six-days' bicycle race at Madison Square Garden, New York city, last October, rode for 127 hours of the 142 allotted to the race, covering 1466 6-10 miles during that time, showing an average speed of 11-1/2 miles an hour. His record is the best ever made, far exceeding any previous attempts in a six-days' match. 2. There are probably several bicycle clubs in your vicinity. Make inquiries, and, if so, you should experience no difficulty in being elected a member of any one of them. AN AZTEC PRINCE.--The largest tunnel in the world is that of St. Gothard, on the railroad line between Lucerne and Milan. The summit of this tunnel is 990 feet below the surface at Andermatt, and 6600 feet beneath the peak at Kastelhorn of the St. Gothard group. The tunnel itself is 26-1/2 feet wide, and 19 feet 10 inches from the floor to the crown of the arched roof. Its length is 9-1/2 miles, while the Hoosac Tunnel, on the Fitchburg Railway, is 4-1/2 miles long. The Mont Cenis tunnel is one and five-eighths miles shorter than that of St. Gothard. IMPATIENT.--1. All communications intended for this paper should be addressed to "James Elverson, Publisher of GOLDEN DAYS, Philadelphia, Pa." If they contain queries intended for this department, that fact should be indicated by writing in the lower left hand corner of the envelope the words "Letter Box," and the real name of the writer in addition to the assumed title, should be placed at the end. 2. A chapter on polishing horns, bones, shells and stones was presented in Vol. 5, No. 43. 3. Oiliness of the skin may be remedied by washing with water containing a teaspoonful of borax or a tablespoonful of alcohol. W.M.R.--Boys ranging in age from fifteen to eighteen years, from any part of the country, may enlist as naval apprentices on the U.S. training-ships, but not on the school-ships Saratoga or St. Mary's, which are, in reality, local institutions, supported by New York city and Pennsylvania. An excellent idea of the requirements in either case may be gained by reading the articles headed "The Nautical School of New York City," in No. 35, Vol. 8, and "Uncle Sam's Ships," in No. 18, Vol. 10. The school-ship boys serve but two years, while the naval apprentices remain until they reach the age of twenty-one, unless sooner discharged for misbehavior or disability.