�If you have lenses you are not using, emulate the example of this man and enlist them in the army. The officer shown in the picture above is Captain Dawson, who used to make photo- graphs for the "Popular Science Monthly"
Have You a Camera Lens? Enlist It in the Army
THE Signal Corps of the Army needs lenses for cameras to be used by the fleet of observation airplanes now being built. If you have a lens of the required type, do your bit by enlisting it in the service of the Army. Write to the photographic division of the Signal Corps, U. S. A., Mills Building Annex, Washing- ton, D. C, stating what you have on hand and what price you want.
Because the camera lens is the eye of the Army and because German lenses can no longer be bought, a serious situa- tion has arisen. The Bureau of Standards, of the Depart- ment of Com- merce is now perfecting a substitute for the German "crown bari- um" glass.
��Popular Science Monthly
1,1 IS Hi «. _^ A Battleship Made of Stone — A
Landlubber's Feat
/XLTHOUGH four months of his Ix vacation went into the building of a stone battleship, John von Wiegand of Brooklyn, N. Y., is proud of the monument which tops a little hill of broken rock, overlooking a stone quarry at Haines Falls, N. Y., in the heart of the Catskill Mountains.
Mr. von Wiegand is a retired police inspector, having passed the age limit of the service. A little over a year ago he spent his vacation in the Catskills and conceived a plan for building a structure out of stone. His choice settled on a battleship.
A number of boys, seeking some form of diversion, soon became inter- ested in Mr. von Wiegand's plan. To each one he gave a time card on which was kept an accurate record of the working hours. So, aided by his staff of juvenile engineers, the former police inspector constructed his battle- ship step by step.
The ship measures twenty-eight feet in length and eight feet in beam. It is built entirely of flat stone slabs of varying sizes and shapes. The funnels consist of short lengths of tree trunk, with the bark left on. The masts are merely young trees with the branches stripped. The decks and roof of the superstructure are of large flat slabs of rock, such as are used for sidewalks, while the turrets are shaped with curved stones and armed with "guns" made of young tree trunks, stripped of branches and bark. No cement or mortar has been used for holding the stones together, since the weight of these compo- nents is suffi- cient to keep them in place. In the vitals of the battle- ship has been placed a bottle containing a record of the names of the con- structors.
���A battleship twenty eigj flat slabs of stone. The
��it feet long, which is built of funnels are short tree trunks
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