The idea of transmutation, in the country of its origin, had a philosophical basis, and was linked up with the Greek theories of matter there current; thus, by supplying a central philosophical principle, it to some extent unified and focussed chemical effort, which previously, so far as it existed at all, had been expended on acquiring empirical acquaintance with a mass of disconnected technical processes.
The top is closed by a pressure-tight window, inside of which is a prism which reflects the light rays vertically down the tube to a prism at the bottom end, where they are reflected in a horizontal direction and focussed in an eyepiece attached to the bottom of the tube.
The telescope must be focussed on the edge of the quartz plate, and in order that all points of the field may be illuminated by the same part of the source, the flame must be so placed that its image is thrown by the lens on the diaphragm of the object glass of the telescope.
The resulting degrees combine intellectually coherent breadth of study with focussed depth in the honors years.
Horizontal rays of light entering at the top were reflected by a prism down the tube and focussed on to a sheet of paper in front of the helmsman inside the submarine.
In Greece the idea of a fundamental unity behind the plurality of phenomena was present, though vaguely, in the minds of the early physicists (see Ionian School), but the first thinker who focussed the problem clearly was Xenophanes.
The eye must be focussed on the edge of the plate, and the two halves of the field will only be equally dark when the principal plane of the plate is parallel to the primitive plane of polarization.
The movements of the apparatus, which when complete should consist of two similar pendulums in planes at right angles to each other, are recorded by means of a beam of light, which, after reflection from the mirror or mirrors, passes through a cylindrical lens and is focussed upon a moving surface of photographic paper.