ing Company, Pittsburgh, Pa.

Deoxidized Bronze. Patent for machine and engine journals.
Philadelphia Smelting Co., Phila., Pa.

For Sale.--4 H. P. Vertical Engine and Boiler (New York Safety Steam
Power Co.'s make), as good, and in some respects better, than new.
Address H. M. Quackenbush, Herkimer, N. Y.

Wood-working Machinery, Waymouth Lathes. Specialty, Wardwell Patent
Saw Bench; it has no equal. Improved Patent Planers; Elevators; Dowel
Machines. Rollstone Machine Company, Fitchburg, Mass.

Galland & Co.'s improved Hydraulic Elevators. Office 206 Broadway, N.
Y., (Evening Post Building, room 22.)

The only economical and practical Gas Engine in the market is the new
"Otto" Silent, built by Schleicher. Schumm & Co., Philadelphia, Pa.
Send for circular.

Dead Pulleys that stop the running of loose pulleys and their belts,
controlled from any point. Send for catalogue. Taper Sleeve Pulley
Works, Erie, Pa.

_Vick's Illustrated Monthly Magazine_ is one of the most beautiful
magazines in the world. Each number contains a chromo of some group of
flowers, and many fine engravings. Published monthly at $1.25 per
year. Address James Vick, Rochester, N. Y.

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[Illustration: Notes and Queries]

NOTES & QUERIES

HINTS TO CORRESPONDENTS.

No attention will be paid to communications unless accompanied with
the full name and address of the writer.

Names and addresses of correspondents will not be given to inquirers.

We renew our request that correspondents, in referring to former
answers or articles, will be kind enough to name the date of the paper
and the page, or the number of the question.

Correspondents whose inquiries do not appear after a reasonable time
should repeat them.

Persons desiring special information which is purely of a personal
character, and not of general interest, should remit from $1 to $5,
according to the subject, as we cannot be expected to spend time and
labor to obtain such information without remuneration.

* * * * *

(1) S. Q.--The speed of a circular saw at the periphery should be from
6,000 to 7,000 feet per minute. The number of revolutions per minute
will of course vary with the diameter of the saw.

(2) T. J. F. asks (1) for the best way to fasten emery on a wooden
wheel, to be used in place of a solid emery wheel. A. Cover the wheel
with leather devoid of grease, and coat the leather surf