L. Lat. [from ardere, to burn.] In old English law. Burning, or melting; the trial or assay of money by fire after it was coined, in order to test its purity. A term frequently used in Domesday Book. Spelman. Reddit tot libras ad arsuram; pays so many pounds according to the test by fire; that is, so many pounds of lawful, approved or tried money. Cowell. The process is described at large in the Black Book of the Exchequer. The loss of weight occasioned by this process. A pound was said to burn so many pence (tot ardere denarios) as it lost by the fire. Spelman. to the criminal how to conduct himself in it; or, 3. by his assistance in the execution of it. Ersk. Inst. ub. sup. See De arte et parte. "In order to make out a party guilty of theft, art and part, it is not necessary to prove that there was any previous concert between him and the actual thief, or that he knew, some time before, that a theft was to be committed. It is sufficient if the party was conscious of what was going on at the time,-if he knew that some article, no matter what, was about to be stolen. If there was privity, even by so slight a communication with the actual thief as a nod or a wink, that would make the party so privy guilty of theft art and part. On the other hand, if the theft was really completed and over, however short the interval, if there was one, between the act and the guilty knowledge,―say that the communication was made behind a screen, or outside the door of the room, after the article was actually taken,-that would change the nature of the offence, and make it reset." Lord Justice Clerk, Arkley's R. 136. The derivation of this phrase is uncertain. Sir George Mackenzie, in his "Discourse upon the laws and customs of Scotland in matters criminal," says that by art is meant that the crime was contrived by the art or skill of the accused, (eorum arte;) and that by part is meant that they were sharers in the crime committed, (et quorum pars magna fui.) By other writers it has been considered as an abbreviation of the Latin phrase artifex et particeps. See P. Cyclopedia. The following expressions occur in Pitcairn's Criminal Trials: "Delatit [accused,] off arte and parte." Vol. 1, part 1, p. 1. "Dilaitit of airt and pairt." Id. p. 133. "Under the pain of being held as arte and pairt-takeris." p. 307.