| Edinburgh encyclopaedia - 1830 - 856 pages
...is employed for the purpose of illuminating the object should have as small a diameter as possible. In the daytime it should be a single hole in the window-shutter of a darkened room, and at night it should be an aperture placed before an Argand lamp. Sol» 7. In all cases, and particularly when... | |
| Denison Olmsted - 1832 - 402 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating...the object should have a very small diameter. In the day time, it should be a single hole in the window shutter of a darkened room, and at night an aperture... | |
| Denison Olmsted - 1835 - 374 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating...the object should have a very small diameter. In the day time it should be a single hole in the window shutter of a darkened room, and at night an aperture... | |
| Sir David Brewster - 1838 - 432 pages
...and look horizontally, parallel •markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating fluid descends over the cornea. 6. Every part of the object should be excluded, except that which is under immediate observation. 6.... | |
| David Brewster - 1841 - 432 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating...which is under immediate observation. 6. The light wliich illuminates the object should have a very small diameter. In the day-time it should be a single... | |
| Denison Olmsted - 1844 - 618 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical; viz. the direction in which the lubricating...diameter. In the daytime it should be a single hole in the window shutter of a darkened room, and at night an aperture placed before an argand lamp. 7. In all... | |
| Denison Olmsted - 1844 - 610 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating...diameter. In the daytime it should be a single hole in the window shutter of a darkened room, and at night an aperture placed before an argand lamp. OPTICS. Fig.... | |
| David Brewster - 1845 - 436 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical ; viz. the direction in which the lubricating...diameter. In the day-time it should be a single hole in tha window-shutter of a darkened room, and at night an aperture placed before an Argand lamp. 7. In... | |
| Denison Olmsted - 1850 - 624 pages
...up and look horizontally, parallel markings or lines will be seen most perfecMy when their direction is vertical ; viz. the direction in which the lubricating...object should be excluded except that which is under immt diate observation. 0. The li^ht which illuminates the object, should have a very small diainelcr.... | |
| Joseph Henry Wythe - 1851 - 204 pages
...and look horizontally, parallel markings or lines will be seen most perfectly when their direction is vertical; viz., the direction in which the lubricating...In the day-time it should be a single hole in the window shutter of a darkened room, and at night an aperture placed before an Argand lamp. 7. In all... | |
| |