A piece of the ordinary sensitized paper, such as is used for photographic printing, when exposed to the action of the light for twenty seconds, at a distance of 2 feet from the reflector, was darkened to the same degree as was a piece of the. Journal of the Franklin Institute - Page 399by Franklin Institute (Philadelphia, Pa.) - 1866Full view - About this book
| Royal Society (Great Britain) - 1867 - 662 pages
...from the reflector, was darkened to the same degree as was a piece of the. same sheet of paper when exposed for a period of one minute to the direct rays...noon, on a very clear day in the month of March. The extraordinary calorific and illuminating powers of the 10-inch machine are all the more remarkable... | |
| 1866 - 642 pages
...from the reflector, was darkened to the same degree as was a piece of the same sheet of paper when exposed for a period of one minute to the direct rays...noon on a very clear day in the month of March. The extraordinary calorific and illuminating powers of the io-inch machine are all the more remarkable... | |
| 1866 - 658 pages
...from the reflector, was darkened to the same degree, as a piece of the same sheet of paper was when exposed for a period of one minute to the direct rays...mid-day sun was shining brightly in at the window. He took the opportunity of roughly comparing the intensity of the sun, with that of the electric light... | |
| 1866 - 736 pages
...from the reflector, was darkened to the same degree, as a piece of the same sheet of paper was when exposed for a period of one minute to the direct rays...mid-day sun was shining brightly in at the window. He took the opportunity of roughly comparing the intensity of the sun, with that of the electric light... | |
| 1866 - 636 pages
...from the reflector, was darkened to the same degree as was a piece of the same sheet of paper when exposed for a period of one minute to the direct rays...noon on a very clear day in the month of March. The extraordinary calorific and illuminating powers of the io-inch machine are all the more remarkable... | |
| 1866 - 638 pages
...from the reflector, was darkened to the same degree as was a piece of the same sheet of paper when exposed for a period of one minute to the direct rays of the sun at noon on a very clear day_ in the month of March. The extraordinary calorific and illuminating powers of the io-inch machine... | |
| Royal Society (Great Britain) - 1867 - 654 pages
...from the reflector, was darkened to the same degree as was a piece of the same sheet of paper when exposed for a period of one minute to the direct rays...noon, on a very clear day in the month of March. The extraordinary calorific and illuminating powers of the 10-inch machine are all the more remarkable... | |
| Johannes Rudolf Wagner - 1872 - 808 pages
...from the reflector, was darkened to the same degree as a piece of the same sheet of paper was when exposed for a period of one minute to the direct rays...at noon on a very clear day in the month of March. Paper could be easily set on fire with a burning-glass introduced in the path of the rays from the... | |
| Johannes Rudolf Wagner - 1872 - 790 pages
...from the reflector, was darkened to the ваше degree as a piee* of the same sheet of paper was when exposed for a period of one minute to the direct rays of the sun at noon on a very clear day in the mouth of March. Poper could be easily set on lire with a burning-glass introduced in the path of the... | |
| Johannes Rudolf Wagner - 1872 - 786 pages
...from the reflector, was darkened to the same degree as a piece of the ваше sheet of paper was when exposed for a period of one minute to the direct rays of the sun at noon ou a ver}' clear day in the month of March. Paper could be easily set on fire with a burning-glass... | |
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