How To Tell A Good Camera. As a usual thing, the modern American camera of the best quality is assuredly "all right" at the time of purchase. It may be well, however, to know how to test its quality. It may "leak" light If it does, it will fog and spoil every sensitive plate you trust to its care. To prove its good faith with you, cap the lens, remove the ground - glass, and, with focussing - cloth tightly over you camera and your head, peer into it for intruding beams of light If none are seen, your camera is so for fruitless. Now you understand that the inside of your "ground-" or focussing" glass receives the reduced inverted image of the object you are about to photograph, and that by the adjustment of the lens you there secure it defined to the highest degree. This surface is replaced by the sensitive film, when you are about to expose, and the last must take the place of the first ex-actly. or your picture will be "out of focus" - illy defined. Therefore, if you have focussed carefully upon an object, and after taking a picture you find that the object is not defined so accurately as you saw it upon your ground - glass - as it should be then there is a lack of coincidence between the chemical and visual or actinic foci; the camera is at fault, and must be so altered to produce the proper result.