The daily Alaskan., 1915-12-30
TESTING A SHELL.
OrdeaIs Through Which a Big Gun
 Missile Must Pass.
THE SOFT NOSE PROJECTILE.

It's Ability to Bore It's Way Through
 Heavy Armor Plate Without ENPIod-
 ing Until After It's Impact Was Dis
 covered by Accident.
 Everybody knows that the modern shell Is one of the most di0bolical of mans inventions, but how many of us realize that 1t is also one of the most delicate and complicated!
 Recently some firms holding con tracts for making high explosive shells took upon themselves to "correct' detail in the specification, and, as a re. suit, a certain thread was "Improved.' " They will never do anything of the kind again, because all their work was reflected. The apparent Ubsurdity-it is. In fact. an absolute absurdity, from an engineering point of Yiew-is de. signed of set purpose.
 There Is a somewhat similar anom' aly in the big shell for penetrating armor plating. which was introduced in consequence of an accident. One dav n test shell was fired at a piece of ormor plating from the soft side, and the projcctlle went clean through II and exploded after impact, whereas similar shell fired against the front the hardened and tempered slde-shat- tered and left an iudcntation of only few inches
 This singular incident set somebody thinking, and in consequence the hlgh explosive armur piercing shell Is now given a soft nose. To the hard point Is attached Q cup of soft metal with which addition 1t will go through the toughest piece of urmor plate. What happens on impact seems to be this: The cap spreads, holding the point and so enabling it-remcmbcr thut the shell Is revolving rapidly-to force its way uDbroken through the hard face of the plate by a sort of boring action.
 No less curious Is another fact con- corning the points of such projectilcs. After the heads have been worked the shells are left for weeks before they undergo the next stage, because, strong as they look. they are liable to snap.
 Why? Think of the razor. Constant stropping twists the grain, with the re sult that the steel gets "tired' and VIII not yield a keen edge. But if you put the thing away for few weeks the rroin win return tO it's normal state, and you can get a satisfactory shave. i In similar way the grain of the steel is affected by working though of course to q much greater extent, and until 1t IS | "set" the makers must go cautiously.
 Steel shows a like ccCeuticity in the making of test gauges. Some of the measurements of shells are very fine, land the instruments employed are so delicate that they have to be used quickly lest the heat of tAe hand causes the metal to expand.
 Now, when a groove is cut in a piece of steel which is to he used as a test gauge the work is laid aside for weeks, perhaps months. Why not finish it at once? Because the groove, though dead true when cut out, may bn otherwise in short time. even though it has been absolutely untouched.
 As a concrete proof of the elaborate nature of projectiIc making take the | case of the shrapuai shell The steel portion undcrgOcs about score of op i eratons, and the brass cartridge case attached to the base requires about six. teen. counting from the disk of sheet | brass to the finished article. Then there Is the fuse. the deliracy of which resembles watchmIking
 Altogether the shell is subjected to about forty inspections and may be re- l jeCted at any stage.
 After shell has survived this ordeal