[ad. med.L. tractiōnem (Albertus, a. 1250), n. of action from trahĕre, tract-um to draw. So F. traction, Sp. traccion, Pg. tracção, It. trazione.]
1. The action of drawing or pulling; draught: opposed to pulsion or pushing, and (in Dynamics) to pressure.
Force of traction, the force exerted in or required for traction. Line of traction, the line along which this force acts. Angle of traction, the angle between the line of traction and the surface along which the body is drawn.
1656. trans. Hobbes’ Elem. Philos. (1839), 343. Motion is distinguished into pulsion and traction.
1837. Whewell, Hist. Induct. Sc. (1857), II. 32. Bodies, on which pressure and traction are exerted.
1843. Penny Cycl., XXV. 109/2. When the angle of traction … is 15 or 16 degrees, a horse pulls with good effect…. An example of the force of traction exerted by steam.
1868. Duncan, trans. Figuier’s Insect W., Introd. 25. The cockchafer … possesses a power of traction equal to more than 14 times its own weight.
b. Phys. and Path. A drawing or pulling of a part or organ (in an animal or plant) by some vital process, as the contraction of a muscle, or the tension of some adherent part.
1615. Crooke, Body of Man, 544. In the traction of the first the lid is depressed; in the traction of the latter it is lifted vp.
1669. Holder, Speech, 163. The Malleus, being fixed to an extensible Membrane, follows the Traction of the Muscle.
1802. Paley, Nat. Theol., xi. (ed. 2), 222. The claws do their office in keeping hold of the support … by the traction of the tendons, in consequence of the attitude which the legs and thighs take by the bird sitting down.
1875. Bennett & Dyer, Sachs’ Bot., 728. The layers which are less turgid and grow more slowly are exposed to a passive traction which promotes their growth.
1876. Clin. Soc. Trans., IX. 192. There was … a slight … traction of face to the right side when the patient laughed.
c. A drawing or pulling movement used in massage, etc.: in quot. 1841 applied to the use of metallic tractors (see TRACTOR 1).
1842. Fraser’s Mag., XXV. 89. The effects produced by traction, or the rubbing of metallic tractors, tipped with little lumps of wax, on the parts affected by pain, are well known.
1887. D. Maguire, Art Massage, iii. (ed. 4), 51. Tractions are movements used on the articulations by pulling one part while holding the other.
1901. Westm. Gaz., 28 Nov., 10/2. Traction of the tongue—that is, moving it about in a rhythmical manner—has produced wonderful results in restoring the apparently dead (especially children) to life. Dr. Laborde, of Paris, is the discoverer of the treatment.
d. fig. Drawing, attraction, attracting power.
1608. Middleton, Mad World, III. A chin-cloute is of that powerfull a traction I can tell you, twill draw more Linnen toot.
1649. E. Reynolds, Hosea, v. 18. Our conversion and sanctification comes from … a supernaturall and omnipotent traction.
a. 1711. Ken, Christophil, Poet. Wks. 1721, I. 425. His Love in Suavities distills, Preventions, Tractions sweet, Devout Christ-hymning Heat.
1883. A. H. Welsh, Eng. Lit., I. VI. 384. He [Macbeth] feels the resistless traction of fate.
2. spec. The drawing of vehicles or loads along a road or track; esp. in reference to the power by which this is done, as horse, steam, electric traction.
1822. Imison, Sc. & Art, I. 27. Dividing the beam … that the point of traction may be as much nearer to the stronger horse.
1826. J. Adamson, Sk. Inform. Rail-roads, 38. Every change which has in any degree to render the way more smooth … added to our powers of tracktion.
1902. Daily Chron., 1 July, 4/6. The three stages are horse-traction, steam traction, and electric traction.
b. transf. (a) A vehicle driven by some special power, as a motor car. nonce-use. (b) Stock Exch. Stocks connected with traction, as tramways, etc.
1896. Westm. Gaz., 13 Nov., 5/2. They attended the Court, having ridden in ten miles on the offending traction.
1903. Daily Chron., 5 Nov., 8/7. The victory for Tammany early in the session reflected strength in tractions and other municipal utility stocks. Ibid. (1905), 4 May, 5/2. Prices worked lower. Coalers and tractions showed some strength.
3. Short for force of traction (as a measurable quantity); the amount of rolling friction (also traction of adhesion) as measuring this (quot. 1877).
1825. J. Nicholson, Operat. Mechanic, 666. If the speed be increased from six miles an hour to eight, the horses have by no means 1-4th less work to do, supposing the friction a constant quantity, and the traction consequently the same.
1838. Civil Eng. & Arch. Jrnl., I. 350/1. A dynamometer, by which the traction might be measured with considerable accuracy.
1877. Knight, Dict. Mech., Traction, the adhesive friction of a wheel on a rail, a rope on a pulley, etc.
4. attrib. and Comb., as traction company, installation, instrument, movement, power; traction aneurism, diverticulum (see quots.); traction-gearing, an inexact name for friction-gearing (FRICTION sb. 5); traction-load, the weight of a locomotive engine or motor car which presses the driving-wheels upon the rail or ground so as produce the requisite adhesive friction and prevent the wheel from slipping; traction-splint (Surg.), a splint with an attachment for pulling upon the limb; traction-wheel, a driving-wheel.
1891. Cent. Dict., *Traction-aneurism.
1899. Syd. Soc. Lex., T[raction] aneurism, an aneurism most commonly seen in children, due to traction of the aorta from an incompletely atrophied ductus Botalli.
1897. Allbutt’s Syst. Med. III. 364. *Traction diverticula generally occur on the anterior wall of the œsophagus.
1899. Syd. Soc. Lex., T[raction] diverticulum, a circumscribed sacculation of the œsophagus from the traction of the circum-œsophageal adhesions.
1877. Knight, Dict. Mech., *Traction-gearing, an arrangement for turning a wheel and its shaft by means of friction or adhesion.
1879. St. George’s Hosp. Rep., IX. 501. On three eyes a *traction instrument was used.
1887. D. Maguire, Art Massage, iv. (ed. 4), 106. Executing … some *traction movements.
1908. Westm. Gaz., 13 Feb., 5/2. American machines … are geared so low as to give them a maximum of *traction power at the expense of speed.
1877. Knight, Dict. Mech., *Traction-wheel, a wheel employed in drawing or impelling a vehicle, as the driving-wheel of a locomotive or traction-engine.
Hence Tractional a., of or pertaining to traction.
1877. Knight, Dict. Mech., s.v. Traction, The tractional surface of a driving-wheel is the face of its perimeter.
