The water-proof is alone to be depended on to detect minute clusters of cavities in the bore, which for this purpose should be perfectly dry, and examined by sunlight. All inspections, consequently, should take place in fair weather, and when the temperature is above the freezing-point.
MARKING GUNS.
33. Guns for the naval service, received by authority of the Bureau of Ordnance, are to be marked in the following manner, viz.:
On the cylinder, in the line of sight near the sight-mass, all accepted guns are to have stamped an anchor two inches long.
Drawings of these stamps will be furnished by the Bureau of Ordnance.
On the base ring or line, the initials of the foundry, the register number, and the weight of gun in pounds.
On the right trunnion, the calibre and year of fabrication.
On the left trunnion, the letter P. and the initials of the inspecting officer; all the above in one-inch letters.
On the upper jaw of the cascabel, the preponderance in pounds to be stamped lightly with half-inch figures.
On the end of the upper jaw, the cascabel block and head of the pin, the foundry number in quarter-inch figures.