a. (and sb.). [See UNI- and POLAR Cf. F. unipolaire.]
1. Electr. Produced by, proceeding from, one magnetic pole; exhibiting one kind of polarity.
1812. Sir H. Davy, Chem. Philos., 168. There are substances that are imperfect conductors which are capable of receiving only one kind of electricity … and which M. Ehrman … has named unipolar bodies.
1873. J. C. Maxwell, Electr. & Magn., II. 7. The property produced by magnetism in transparent bodies of twisting the plane of polarization of the incident light, is, like magnetism itself, a unipolar property.
1881. Nature, XXIII. 616. To illustrate unipolar conductivity. Ibid., XXIV. 570. Whether it be not possible entirely to separate one from the other, and to produce what may be called a unipolar discharge.
1888. Encycl. Brit., XXIII. 330/1. The so-called ‘unipolar’ induction supposed to be due to the rotation of the earth.
b. Of apparatus: Having, or operating by means of, one magnetic pole. Also ellipt.
1876. Nature, XIV. 263/2. A unipolar magnetic needle. Ibid. The space through which a subsidiary magnet must be moved in order to restore the unipolar to its original position.
1883. Daily News, 10 Sept., 2/2. The remarkable machine of Messrs. Siemens and Halske, called the unipolar machine.
1884. Health Exhib. Catal., 79/2. A true unipolar continuous current dynamo.
2. Biol. Of nerve-cells: Having one pole or fibrous prolongation; connected to the nerve-fiber by a single fibrous process.
1859. Todd’s Cycl. Anat., V. 436/2. Those [ganglionic corpuscles] from which one tube proceeds are termed unipolar.
1873. A. Flint, Physiol. Man, Nerv. Syst., i. 46. Unipolar cells exist in some of the lower orders of animals.
1880. Bastian, Brain, ii. 48. Unipolar nerve cells … are alleged to exist in the ganglia on the spinal nerves and elsewhere.
b. (see quot.)
1878. F. J. Bell, trans. Gegenbaur’s Comp. Anat., 597. If the rete remains broken up, then it is known as a diffuse, unipolar, or monocentric rete mirabile.
Hence Unipolarity, the condition or character of being unipolar. (Cf. F. unipolarité.)
1888. Philos. Mag., Ser. V. XXVI. 129. We do not believe that Ohm ever observed the phenomenon of unipolarity in strong sulphuric acid with [etc.].
