1779 J. A. De Luc in Philos. Trans. 1778 (Royal Soc.) 68 487 If we wish for an Hygrometer, an Electrometer, a Photometer [Fr. un Photomètre].

1794 Count Rumford in Philos. Trans. (Royal Soc.) 84 73 I have now brought the principal instrument to such a degree of perfection, that, if I might without being suspected of affectation, I should dignify it with a name, and call it a photometer.

1869 Nature 2 Dec. 139/2 The amount of light given by the corona. This was estimated by a photometer. consisting of a wedge of dark glass, with a moveable slit.

1893 Brit. Jrnl. Photogr. 40 811 Very many different patterns of photometers have been introduced and used during the last thirty years.

1911 Astrophysical Jrnl. 34 108 With the selenium photometer attached to our 12-inch telescope the measures are ordinarily limited to stars brighter than the third magnitude.

1930 Movie Makers Feb. 67/1 (advt.) The B & H Photometer, first introduced for gauging exposure for Filmo movie cameras, is not presented for use with ‘still’ cameras.

2002 Ann. Bot. 89 12/2 The concentrations of NH₄⁺ and K⁺ were monitored automatically..by an ion selective electrode system..and flame photometer.

1895 Science 20 Sept. 353/1 The easy and accurate comparison of lights, etc., upon an ordinary photometer bench.

1999 Business Wire (Nexis) 12 Apr. The MLT 4 is designed to measure up to five gas components and is available with two dual photometer benches.

1899 Proc. Royal Soc. 65 487 A device worked by an electric current from a key placed under the photometer head.

1973 W. Thomas SPSE Handbk. Photogr. Sci. & Engin. ii. 153 Photometer heads are used in conjunction with some means for varying the luminance of one or both surfaces in a known manner so that a photometric balance may be obtained.

1900 Jrnl. Franklin Inst. 149 291 The leading makers now photometer each and every lamp, and the practice of photometering a few and picking out the remainder by the eye is past.

1923 Amer. Jrnl. Sci. 205 459 The films were photometered with a microphotometer at the Bureau of Standards.

1966 D. G. Brandon Mod. Techniques Metallogr. iii. 127 The minimum area that can be photometered is principally limited by the size of the diffraction image of the spot selected for photometry.

1998 Astron. Jrnl. 115 573 The dwarf irregular galaxy Holmberg II..has been observed on 34 separate nights for the purpose of finding and photometering variable stars.

1907 Amer. Naturalist 41 669 Similar boxes are illuminated either by photometered lamps of different intensity or by colored lights.

1994 Astrophysical Jrnl. 423 305 An ultraviolet color-magnitude diagram based on the 46 well-photometered stars that appear in both images is presented.

1917 Physical Rev. 10 695 The photographs taken thus far are not suitable for photometering, but arrangements are complete for taking such photographs, and for measuring the intensity of the lines.

1977 Solar Syst. Res. 10 198 The results of visual mapping and photometering of Saturn in 1973 and 1974 are shown.