Marine, is a espy of Theodor de Bry's "Voyages" passages of which were obliterated three hundred years ago by a censor of the Spanish Inquisition. "His expurgation was done apparently very effectively, by means Of an ink applied 20 thickly in parts that it could be felt as a ridge by the Singer. Little did he realize, how-fever, that his black ink was as trans-arent to infra-red light as is water visible light, Dr. L. Bendikson, Photographing these documents with Infra-red camera, has defeated the censor as clearly as if the ehliter tion had never been done.
"Tafra-red light possesses the valu ble property of Being able to-penetrate atmospheric haze. It is generally. Impossible to take a photograph over'a very great distance, because the blue light to which an ordinary plate or firn most readily responds seatiered by the haze and so Drg vents the distant detail being re~ corded. With plates treated with dyes, so as to make them sensitive to the infra-red light, however, it is quite another story. Using the invisi-Bie Tigh, which passes, hrough baze fas daylight pastes through a window, details of the those distant objects can bbe recorded, limited only by the curvvature of the earth. In this way,
height of 29,000 test" over, Salim, california, was able to photograph 'Mount 'Shasta, more than' 830 miles away. The mountain was quite me Visible to him, and he had to orient Fis camera by compass.
Text read from the printed page and cleaned; old type leaves the occasional error.