This working standard should be maintained at a fixed distance on one side of the photometer, such that when worked at a standard voltage it creates an illumination of one candle-foot on one side of the photometer disk.
The incandescent lamp to be examined is then placed on the other side of the photometer disk on a travelling carriage, so that it can be moved to and fro.
When only the mean spherical or mean hemispherical candle-power is required the process can be shortened by employing an integrating photometer such as that of C.
All readings were made by a Lummer-Brodhun photometerand the voltmeters and ammeters used were carefully standardized.
A valve is then fitted to one of the front openings, so that the light in that half of the photometer may be gradually diminished.
From time to time during the exposure the print in the photometer is examined, and when a certain picture is printed to a certain shade, or when the one next by commences to appear or is faintly printed, etc.
To print, the tissue is laid over the negative, taking care that it covers the safe edge, and a strip of silvered paper placed in the photometer, then both the printing frame and the photometer are exposed to light side by side.
In the photometer used by the German astronomers the image of one star is compared with an artificial star formed by the flame of a candle.
Thus, all the photometer can do is to give us the means of increasing or diminishing the light from one star, so that we can make it equal by estimation to that from some other star or source of light.
The photometerobservations show a greater degree of sun's light on the hills than below, but there is not at either station a decided relation between the indications of this instrument and the black-bulb thermometer.
At the same time, the black bulb thermometer, fully exposed on the snow, rose 54 degrees above the air, and the photometer gave 10.
A goodPhotometer being still a desideratum, I had recourse to the old wedge of coloured glass, of an uniform neutral tint, the distance between whose extremes, or between transparency and total opacity, was one foot.
My black glassphotometer shut out the sun's disc at 10.
The photometer may show a very adequate intensity of illumination; nevertheless seeing may be unsatisfactory or even impossible.
This problem can be solved by means of the photometerand a formula provided, which states, for example, that a certain percentage of the total area be painted in gray, another percentage in green, and so on.
In such a case the photometer yielded results quite likely to be misinterpreted as satisfactory.
They had been photometered carefully by two observers by means of a Lummer-Brodhun photometer and a Hefner amyl acetate lamp previous to their use in the experiment.
For measuring the mean spherical intensity a photometerdevised by Professor Matthews of Purdue University is employed.
When incandescent lamps are brought to a photometer they are as a rule placed on a spindle turning so swiftly that their mean horizontal candle-power may be read at once.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "photometer" in a variety of sentences. We hope that you will now be able to make sentences using this word.
