The vertical retort was one of the first forms experimented with by Murdoch, but owing to the difficulty of withdrawing the coke, the low illuminating power of the gas made in it, and the damage to the retort itself, due to the swelling of the charge during distillation, it was quickly abandoned.
To illuminating oil or kerosene a series of tests is applied in order that the colour, odour, specific gravity and flash-point or fire-test may be recorded.
In any case oil has ever been regarded as the aptest symbol and vehicle of the holy and illuminating spirit.
Wenham, another constructor, did not at first succeed in avoiding the pseudoscopic effect, but, by the application of refracting dividing prisms, he subsequently arrived at orthoscopic representations and continued the development of the different methods for producing microphotographic stereograms; this was effected in the first case by placing a diaphragm over one half of the objective for each exposure, and in the second case by a suitable direction of the illuminating pencil (fig.
BENZENE, C 6 H 6, a hydrocarbon discovered in 1825 by Faraday in the liquid produced in the compression of the illuminating gas obtained by distilling certain oils and fats.
This oil was formerly used for illuminating purposes.
With the .orthogonal arrangement for illuminating and observing the beam of light traverses an extremely fine slit through a well-corrected system, whose optic axis is perpendicular to the axis of the microscope; the system reduces the dimensions of the beam to about 2 to 4 in the focal plane of the objective.
A year later the Duma again came into collision with the government in a matter highly illuminating of the struggle between the ancient traditions and the new ideas in Russia.
But it was not until the middle of the 19th century that its value as an illuminating oil became known, and not until 1859 was the first petroleum well drilled.
By far the most illuminating collection is that of Hugh Elliott, Letters of John Stuart Mill (2 vols., 1910), which contains letters to John Sterling, Carlyle, E.