stack at the front end. I use hard
pine wood for fuel. Will some of your many readers give me the best
way of constructing the flue under the boiler, from the end of the
grate bars to where it enters the flues at the back end, and also
state the proper distance from the back wall to the end of the
boiler?--N. H.

3.--MEDAL CASTS.--I have some medals which I should like to copy.
Having tried several times, and failed, I thought that I would ask
advice through your query columns. I do not know of what the medals
are manufactured. They are, I suppose, made to imitate bronze. I have
tried casting them in plaster of Paris molds, but have had very poor
success, as the surface of the medals was covered with small holes.
The metal used was lead and antimony, seven to one. I should like to
know, if there be any metal that I can cast them of, and bring out the
bronze color afterwards, or if there be any metal that I can cast them
of, and afterwards color by some solution. Also, of what should I make
my molds?--J. E. M.

4.--REMOVING THE TASTE OF TAR FROM RAIN WATER.--Will some of your
correspondents tell me if rain water, which runs off a gravel roof,
and tastes very strongly of tar, is unhealthy, and if there be
anything that will prevent its tasting, as it is very disagreeable for
cooking purposes?--C. E. H.

5.--SORGHUM MOLASSES.--How can I separate the molasses from the sugar,
in sorghum sugar mush, to make a dry merchantable sugar?

6.--FLUX FOR ALUMINUM.--Will some of your readers tell me, through
your columns, the best flux to use in melting and mixing aluminum and
copper?

* * * * *

INVENTIONS PATENTED IN ENGLAND BY AMERICANS.

[Compiled from the Commissioners of Patents' Journal.]

APPLICATIONS FOR LETTERS PATENT.

350.--BREECH-LOADING FIRE-ARMS.--Eli Whitney, New Haven, Conn.
February 10, 1871.

352.--GOVERNOR.--Stilliman B. Allen, ----, Mass. February 10, 1871.

357.--WINDMILL.--A. P. Brown, New York city. February 11, 1871.

332.--FURNITURE CASTERS.--F. A. Gardner and H. S. Turrell, Danbury
Conn. February 8, 1871.

339.--WIRE FABRICS FOR MATTRESSES.--Samuel Rogers, New York city.
February 9, 1871.

340.--SCREW PROPELLER CANAL BOATS.--Thomas Main, Pierpoint, N. Y.
February 9, 1871.

362.--FLYER FOR SPINNING MACHINERY.--Thomas Mayor and Geo. Chatterton,
Providence, R. I. February 14, 1871.

373.--TELEGRAPHIC APPARATUS AND DETECTORS.--W. B. Watkins, Jersey
Ci