After all the little silver bromides that the light shone on have been transformed into metallic silver by the developer, another chemical friend has to step in and carry away all the little bromides that were not awakened by the flash of light. This friend’s name is “Hypo,” and in a few minutes he has carried away all the little bromides that are still sleeping, so that the trundle bed with the now awakened and transformed silver bromides will, after washing and drying, be called a negative, and ready to print your pictures from. If we take this negative, as it is called, and hold it up to the light, we will see that everything is reversed, not only from right to left, but also that whatever is white or light in color is dark in the negative, and that what would correspond to the darker parts of our picture are the lightest in the negative, and it is from these facts that we give it the name negative. Now, to get our picture as it should be, we must place this negative in contact with a sheet of coated paper that is also sensitive to light. So we place the negative and the sheet of sensitive paper in what is called a printing frame, with the negative uppermost, so that the light may shine through the negative, and impress the image upon the sheet of sensitive paper. Now, it stands to reason that if the lightest parts of our picture are the darkest in the negative that less light can pass through such portions of the negative in a given time, so that with the proper exposure to light the image upon the sheet of sensitive paper will be a correct picture of whatever the lens saw. [Illustration: The swiftest thing that the human race has ever put into motion is the steel projectile of a twelve-inch gun. No human eye can follow its flight. Released at a pressure of forty thousand pounds to the square inch--in a heat at which diamonds melt and carbon boils--it hurls through the air at the rate of twenty-five miles a minute, and reaches the mark _ahead of its own sound_! (Pictures and story by courtesy of McClure’s Magazine.)] TWENTY-FIVE MILES A MINUTE AN EXCLUSIVE STORY, ILLUSTRATED WITH A SERIES OF REMARKABLE PHOTOGRAPHS TAKEN WITH THE FASTEST CAMERA IN THE WORLD BY CLEVELAND MOFFETT ~HOW SHOOTING SHELLS ARE PHOTOGRAPHED~