her cause. If the bore is not clean when oiled--that
is, if powder fouling is present or rust has started--a half
inch of cosmic on the outside will not stop its action, and the
barrel will be ruined. Remember that the surface must be perfectly
cleaned before the heavy oil is applied. If the instructions
as given above are carefully followed, arms may be stored for
years without harm.

(j) Preparation of solutions:

_Soda_solution_--This should be a saturated solution or sal
soda (bicarbonate of soda). A strength of at least 20 per cent
is necessary. The spoon referred to in the following directions
is the model 1910 spoon issued in the mess outfit.

Sal soda, one-fourth pound, or four (4) heaping spoonfuls.

Water, 1 pint or cup, model of 1910, to upper rivets.

The sal soda will dissolve more readily in hot water.

_Swabbing_solution_.--Ammonium persulphate, 60 grains, one-half
spoonful smoothed off.

Ammonia, 28 per cent, 6 ounces, or three-eighths of a pint, or
12 spoonfuls.

Water, 4 ounces, or one-fourth pint, or 8 spoonfuls.

Dissolve the ammonium persulphate in the water and add the ammonia.
Keep in tightly corked bottle; pour out only what is necessary
at the time, and keep the bottle corked.

_Standard_metal_fouling_solution_.--Ammonium persulphate,
1 ounce, or 2 medium heaping spoonfuls.

Ammonium carbonate, 200 grains, or 1 heaping spoonful.

Ammonia, 28 per cent, 6 ounces, or three-eighths pint, or 12
spoonfuls.

Water, 4 ounces, or one-fourth pint, or 8 spoonfuls.

Powder the persulphate and carbonate together, dissolve in the
water and add the ammonia; mix thoroughly and allow to stand
for one hour before using. It should be kept in a strong bottle,
tightly corked. The solution should not be used more than twice,
and used solution should not be mixed with unused solution, but
should be bottled separately, The solution, when mixed, should
be used within 30 days! Care should be exercised in mixing and
using this solution to prevent injury to the rifle. An experienced
noncommissioned officer should mix the solution and superintend
its use.

Neither of these ammonia solutions have any appreciable action
on steel when not exposed to the air, but if allowed to evaporate
on steel they attack it rapidly. Care should, therefore, be taken
that none spills on the mechanism and that the barrel is washed out
promptly with soda solution. The first application of soda solution
removes the greater p