1717 Philos. Trans. (Royal Soc.) 30 604 Mr. Gascoigne was the first that measured the Diameters of the Planets, &c. by a Micrometer.

a1719 J. Flamsteed in W. Hone Every-day Bk. (1826) I. 1092 I..had Mr. Townly's Micrometer presented to me [in 1670] by Sir Jonas Moor.

1746 Gentleman's Mag. May 236/2 This micrometer consists of a bit of the finest black silk, which is divided into minute squares..to answer to the diameter of the object to such a degree of accuracy.

1772 Philos. Trans. 1771 (Royal Soc.) 61 536 The two micrometers, as mutually supplying each other's defects.

1829 W. Pearson Pract. Astron. II. 133 La Lande has called reticles (reticules) the most simple kind of micrometer.

1842 W. T. Brande Dict. Sci., Lit. & Art 739/2 The prism micrometer..has this important defect [etc.].

1882 Harper's Mag. Mar. 528/1 For a telescope which has no micrometer, the Huyghenian or negative eyepiece, as it is commonly called, is the best.

1885 C. S. Murray in Brit. Almanac Compan. 120 A collimator..is a telescope furnished with a micrometer at its focus.

1920 Nature 1 July 563/1 Such motion being measured by a plate micrometer or ‘graticule’ in the observing telescope.

1955 H. C. King Hist. Telescope ix. 185 The suspended annular micrometer—a steel ring inserted in a disk of glass placed in the plane of the primary focus.

1992 S. P. Maran Astron. & Astrophysics Encycl. 56/1 Observations are generally characterized by measurements of B relative to A in polar coordinates... Visual observation programs most frequently make use of the filar micrometer to measure these quantities.

1995 A. Chapman Dividing Circle (ed. 2) iii. 40 William Gascoigne, who invented the telescopic sight, was also the first astronomer to mount a moving reticule..to make a filar micrometer.

1790 R. Leslie Let. 1 July in T. Jefferson Papers (1961) XVI. 589 ¹/ _80000. part of the whole length, a fraction scarcely within the power of a micrometer to measure.

1897 Catholic World Apr. 115 Some day we may hope to measure the degree of criminality by a micrometer, or that at least the cephalic index may be some approximation to a standard of measurement.

1903 Jrnl. Royal Statist. Soc. 66 718 Most machinists, nowadays, are familiar with the reading of the decimal divisions in thousands of an inch when using the micrometer.

1918 Amer. Jrnl. Internat. Law 12 4 (Suppl.: Official Documents) 305 Public safety requires that the following articles..micrometers and calipers..shall not..be exported from or shipped from or taken out of the United States.

1933 A. W. Barton Text Bk. Heat iii. 62 The problem resolves itself into the determination of changes in length of the order 1 mm.; the vernier and the micrometer at once suggest themselves.

1951 ‘N. Shute’ Round Bend xi. 337 He had quite a lot of fine precision tools and measuring instruments, micrometers, inside micrometers, feelers, [etc.].

1971 Tools & their Uses (U.S. Navy Bureau of Naval Personnel) (1973) iii. 92 There are three types of micrometers that are most commonly used throughout the Navy: the outside micrometer caliper (including the screw thread micrometer), the inside micrometer, and the depth micrometer.

1993 R. J. Pond Introd. Engin. Technol. (ed. 2) vii. 178 Five pieces from an assembly line have had one quality characteristic, designed to be 5.33 mm, measured by a micrometer as follows: 5.34 mm. 5.30 mm, 5.34 mm, 5.33 mm, and 5.31 mm.

?1790 J. Imison School of Arts (ed. 2) 240 The new micrometer is nothing more than a stage (on which the objects are placed) moveable by a fine screw which has a hand..passing over the divisions of a graduated circle.

1855 G. Busk tr. C. Wedl Rudim. Pathol. Histol. i. i. 10 The glass micrometer..has supplanted the..screw micrometer.

1866 W. T. Brande & G. W. Cox Dict. Sci., Lit. & Art (new ed.) II. 518/1 The instruments in use among microscopists are Jackson's micrometer and the cobweb micrometer.

1877 C. Darwin Different Forms Flowers i. 16 I measured with the micrometer many specimens, both dry and wet.

1961 J. Stubblefield Davies's Introd. Palaeontol. (ed. 3) xii. 260 The accurate measurements of fossils by means of sliding callipers, and in the case of microscopic fossils either by an eye-piece or stage micrometer, is commonly necessary.

1990 Jrnl. Zool. 220 312 From each muscle portion a random sample of fibres was measured on a dissecting microscope equipped with an ocular micrometer.

1898 T. C. Allbutt et al. Syst. Med. V. 443 The lines which form the divisions of the micrometer cell may be made more distinct [etc.].

1914 Proc. Royal Soc. A. 91 82 In order to obtain the requisite thin layers of the liquid, the micrometer cell as previously described was used.

1785 Philos. Trans. (Royal Soc.) 75 468 Projecting above the micrometer head.

1894 Philos. Trans. 1893 (Royal Soc.) A. 184 769 Each wire read on its own micrometer head.

1923 L. C. Martin Colour x. 150 The brightness of the yellow and the ratio of red to green are indicated by the readings on two micrometer heads.

1992 Mech. Products & Tools July 1472/3 The micrometer head also includes a constant force ratchet-stop and positive locking clamp.

1835 A. Ure Philos. Manuf. 96 Micrometer measurements taken from the spectral image..are apt to lead to great fallacies.

1895 Philos. Trans. 1894 (Royal Soc.) A. 185 171 (table) Micrometer measurements in hundredths of an inch.

1922 Bot. Gaz. 73 266 The amount of increase in volume during the first stages of the embryogeny, calculated from micrometer measurements.

1995 Proc. National Acad. Sci. U.S.A. 92 10920 The average injection volume was determined from micrometer measurements.

1883 Encycl. Brit. XVI. 249/2 A dull phosphorescence sufficient to make the micrometer pointer..faintly visible.

1770 Philos. Trans. 1769 (Royal Soc.) 59 269 I therefore took six inches between the fine points of a pair of compasses, from the micrometer scale.

1854 Pereira's Pol. Light 45 A very minutely grooved surface..presents an iridescent appearance in white light... Micrometer scales frequently present the same appearances.

1903 Biometrika 2 256 The measurements were made..under such magnification that a division of the micrometer scale in measuring the body-length was = 0.0320 mm.

1996 Jrnl. Ecol. 84 56 Achene length and width..were recorded using a dissecting microscope and micrometer scale.

1883 Encycl. Brit. XVI. 244/1 The oblong frame, containing the micrometer slides.

1905 Proc. Royal Soc. B. 77 46 The measurements were made with a micrometer eye-piece, gauged against a micrometer slide.

1953 R. W. Fairbrother Text-bk. Bacteriol. (ed. 7) ii. 17 A special micrometer eye-piece, containing a graduated scale which is first gauged by comparison with a standard graduated micrometer slide.

1992 Jrnl. Animal Ecol. 61 586 The magnified post-rostral radius image was then measured and converted to true size using a micrometer slide.

1898 T. C. Allbutt et al. Syst. Med. V. 441 The corpuscles..are reckoned by means of a series of micrometer squares ruled over a certain area of the glass floor of the chamber or cell.

1905 Bull. Torrey Bot. Club 31 532 The average area of the sections was about fifteen micrometer squares.

1862 Internat. Exhib.: Illustr. Catal. Industr. Dept. II. xi. §2612 The tangent back sight is elevated by a rack and pinion, the latter having a micrometer wheel for finer readings.

1895 Amer. Naturalist 29 194 Make transverse sections of it, taking about four to six divisions of the micrometer wheel to each section.

1793 Philos. Trans. (Royal Soc.) 83 95 I made every 10th degree of the circle pass under the micrometer wire of the east microscope.

1806 Trans. Royal Irish Acad. 10 Science 111 In adjusting the telescope and micrometer wires.

1922 Biometrika 14 88 There is a correlation between successive settings of the micrometer wires in the second eyepiece.

1957 Encycl. Brit. XV. 430/2 An image of the micrometer wire, together with the lens-formed region of the photographic plate to be measured, are projected onto a white screen.

1875 E. H. Knight Amer. Mech. Dict. II. 1431/2 Kenshaw's micrometer-balance, invented about 1842, consists of a beam or steelyard supported on a knife-edged fulcrum.

1920 Proc. Royal Soc. 1919–20 B. 91 122 The amount of blood collected weighed about 120 mgrm. to 130 mgrm., and the weighings were done by a specially constructed micrometer balance.

1877 Catal. & Price Lists Brown & Sharpe Manufacturing Co. 49 Micrometer caliper, for machinists' use. Price $9... For all sizes less than one inch diameter, this caliper will be found a reliable and convenient substitute for the vernier caliper.

1884 F. J. Britten Watch & Clockmakers' Handbk. (new ed.) 76 The new one [sc. a plug] may be gauged with a Micrometer or Registering Callipers.

1917 Proc. Royal Soc. 1916–17 A. 93 195 A test bar was prepared..so as to permit of accurate length measurements by means of a micrometer calliper.

1971 Tools & their Uses (U.S. Navy Bureau of Naval Personnel) (1973) iii. 92 There are three types of micrometers that are most commonly used throughout the Navy: the outside micrometer caliper (including the screw thread micrometer), the inside micrometer, and the depth micrometer.

1995 Proc. National Acad. Sci. U.S.A. 92 4824 Swelling was quantitated by measuring the thickness of the foot..and the width of the ankle..with a micrometer caliper.

1834 Philos. Trans. (Royal Soc.) 124 205 Mr. Dollond's ingenious application of the negative achromatic lens to the micrometer eyepiece.

1894 Philos. Trans. 1893 (Royal Soc.) A. 184 397 The galvanometer..was fitted with a microscope containing a micrometer eyepiece by Zeiss.

1953 R. W. Fairbrother Text-bk. Bacteriol. (ed. 7) ii. 17 A more accurate estimation [of the size of bacteria] is now obtained by the use of a special micrometer eye-piece.

1987 Jrnl. Animal Ecol. 56 1004 Organisms were measured later..to the nearest 0.1 mm using a Wild M4A dissecting microscope and micrometer eyepiece.

1879 Proc. Royal Soc. 29 165 A method is introduced of readily estimating such magnitudes between the 1–80,000th and the 1–500,000th of an inch, by means of a micrometer gauge.

1902 P. Marshall Metal Working Tools 10 Another very useful type of gauge for making fine measurements is the micrometer gauge.

1936 E. A. Atkins & A. G. Walker Electr. Arc & Oxy-acetylene Welding (ed. 3) x. 104 The blow-pipe should be cared for by a welder with almost the same amount of care as an engineer usually bestows on a micrometer gauge.

1988 Proc. Royal Soc. B. 234 256 The diameters of the more distal arteries were determined with a micrometer gauge in the microscope.

1785 Philos. Trans. (Royal Soc.) 75 463 The right-hand or micrometer microscope, so distinguished because it has a micrometer attached to it.

1849 R. V. Dixon Treat. Heat i. 25 The microscope e′ was hence called the micrometer microscope.

1906 W. Hallock & H. T. Wade Outl. Evol. of Weights & Measures x. 223 The line standard, of course, can be used with a microscope with cross-hairs, or a micrometer microscope, much more readily than an end standard.

1953 K. J. Hume & G. H. Sharp Pract. Metrol. (1965) ii. xxix. 141 There are two types of auto-collimator in general use; one of low sensitivity, with an accuracy of reading of about 0.2 min, and the others incorporating a micrometer microscope reading to a fraction of a second.

1755 Philos. Trans. 1754 (Royal Soc.) 48 600 The measures taken by this instrument are determined by the contact of a piece of metal with the point of a micrometer-screw.

1788 Trans. Soc. Arts 6 190 Moved by the micrometer screw.

1872 G. R. Cutter tr. H. Frey Microscope & Microsc. Technol. i. 24 The finely constructed micrometer screw, which moves the microscope, is used for more accurate focussing.

1933 A. W. Barton Text Bk. Heat iii. 64 The second accurate way of setting the micrometer screw, namely, by observing the coincidence between the image of a fine line ruled on the bar and the cross-wire of a vertical microscope.

1992 Proc. National Acad. Sci. U.S.A. 89 4245 The control-rod micrometer screw, which is used to set the oil pressure within the probe..is now motorized.