e could be made and set in the center of the
thickness of the chimney, with the space above the top of it open to
the exterior of the house; a very slight structure, simply having a
good floor and roof and open around the sides, and built against the
chimney as an extension to the house, would answer for a summer
kitchen, while the ordinary kitchen inside the house could be used in
winter. The transposition could be made by a pair of iron sliding
doors shutting off the kitchen not in use; and these doors could be
transferred from one side of the chimney to the other when the change
of season required it.

(18) A.X.A. says: In your issue of December 2 is a recipe in which
"insoluble acid chromate of lime," and gelatin are to be used; and in
a succeeding number of your paper the modes of preparing the insoluble
acid are given. I have made the acid according to your directions, but
the result of my manipulation of the recipe is a failure. You say:
"Take of insoluble acid chromate of lime one part, and of gelatin five
parts;" but you do not say what further is to be done. Will the acid
dissolve the gelatin, or must warm water be added? In my experiment
the acid would not dissolve the gelatin, and I had to add considerable
warm water before it would do so. A. Dissolve the bichromate of lime
in the smallest possible quantity of warm water, and filter; then add
the gelatin, previously softened by immersion in cold water. Heat the
mixture over a water bath until the gelatin is completely dissolved,
stir well, and use while hot. The recipe should have stated that this
cement was best suited for glassware. The bichromate of potash or of
ammonia will answer nearly as well as the lime salt.

(19) E.C.N. asks: How must a stove be constructed to burn pea coal,
for heating outbuildings? Is there any way of constructing a draught
below the grate of any common heating stove, sufficiently strong to do
without an extra long chimney? A. Use a broad grate to spread the coal
out well, so as to avoid the necessity of heaping it up much; make the
opening for the draft some distance below the grate, and regulate by
the usual slide dampers in the lower and upper doors.

MINERALS, ETC.--Specimens have been received from the following
correspondents, and examined, with the result stated:

F.R.R.S.--The substance you send is carbonate of iron. It is held in
solution in the water by the large excess of carbonic acid which the
water contains. On