com pass, compas, cumpas

& a. [O. Fr. compas; Sp. compas; Port. compas so, comp aço; Ital. compas so; Low Lat. compa us =a circle, from Lat.com= cum =with, and pa us a pace, a step.] A. As substantive: I. Ordinary Language : 1. Literally : †(1) A circle. [TO FETCH A COMPASS.] "Alle satte atte mete in compas aboute." Chaucer: The Cokes Tale of Gamelyn, 1. 623. *(2) A going round, a circular way or course. "A street was in round IMG:content-0365.png:[blocks in formation] 1. Mechanics : A circumscribing instrument, or one for describing arcs or measurers' lines. 2. Music : The range or power of the voice or of any musical instrument; the extent of notes or sounds po ible to be expre ed by it. "Through all the compa of the notes it ran, The diapason closing full in man." Dryden: Ode on St. Cecilia's Day. 3. Magnetism: An instrument for determining There are many kinds of it; the best known is the direction by means of a poised magnetic needle. mariner's compa . [4.] 4. Naut .: The mariner's compa , which is a declination compa used in guiding the course of a ship. It is generally inclosed in a box, which again is placed in another and larger one, the latter termed the binnacle, the appropriate situation of which is the deck in the after part of the ve el. The magnetized needle, which is the e ential part sin, as; expect, Xenophon, exist. ph = f, The American Dictionary and Cyclopedia of the mariner's compa , is fixed to the lower part of a card, which may be made of ordinary cardboard, of a leaf of mica, or anything similar. By this arrangement, which is the most convenient one, the card revolves with the needle. It is marked not merely with the four cardinal points, but with various minuter divisions so as to constitute 32 in all. To keep the compa in a horizontal position, notwithstanding the rolling of the ship. it is supported on gimbals. In an iron or steel ve el there is a deviation of the north and south line from the magnetic meridian, owing to the permanent magnetism of such a ve el. This is compensated for by placing a permanent steel magnet in the neighborhood of the compa , which exerts an equal and opposite attraction to that due to the ship. It is believed that the mariners compa was in use in China first on land and then, after an interval, to guide ships on the sea. The name of its inventor has not been preserved. Guyot de Provins, a French poet, who in A. D. 1190 wrote a satire called "La Bible," speaks of it, but having been a crusader he may have seen it in the East. It is said to have been brought to Europe by Marco Polo, a Venetian, 1260, A. D. Flavio Gioja, of Amalfi, a navigator, of Naples, is said to have introduced the suspension of the needle, 1302. The compa is also said to have been known to the Swedes in the time of king Jarl Birger, 1250. Its variation was discovered first by Columbus, 1492; afterward by Sebastian Cabot, 1540. The compa box and hanging compa used by navigators were invented by William Barlowe, an English divine and natural philosopher, in 1608. Azimuth Compa : [AZIMUTH.] Declination Compa : An instrument intended to measure the magnetic declination of a place, when its astronomical meridian is known. Inclination Compa : An instrument for measuring the magnetic inclination, or dip. Mariner's Compa : The same as COMPASS, II. 4 (q. v.). Prismatic Compa : The same as AZIMUTH COMPASS (q. v.). Sine Compa : Elect.: A form of galvanometer for measuring powerful currents. Spirit Compa : A form of mariner's compa , in which the bowl or case is hermetically seafed and filled with alcohol or other non-freezing liquid. The compa card is made with hollow compartments so as nearly to float. In this way the friction of the pivot or point of support is greatly diminished, and the compa is far more sensitive. Surveyor's Compa : An instrument used by surveyors for measuring horizontal angles. It consists of a rotating telescope with collimation lines, mounted above a compa . Tangent Compa : Elect.: An instrument for measuring the intensity of a voltaic current in which a small needle is placed. The intensity of such a current being proportional to the angle of deflection, the instrument ascertains this deflection, after which its corresponding value is obtained from a table of tangents, and thus the intensity of the current is measured. *III. In special phrases and compounds : 1. In compa , * in cumpas : (1) Lit .: Around, round about. [A. I. 1.] "Biholdynge hem aboute that saten in cumpas of hym." -Wycliffe: Mark iii. 34. (2) Fig .: Within due limits or bounds; with due moderation. 2. Within compa : The same as in compa (2). *3. To fetch a compa : To go round in a circle, to form a circle or circular line. "And the border shall fetch a compa from Azmon unto the river of Egypt..."- Numb . xxxiv. 5. The expre ion translated in Acts xxvii. 13, "fetched a compa ," appears in the revised version as "made a circuit." *4. To keep compa : To keep within bounds or moderation. " undertaking for him, that he should keep compa ..."-King James: Witty Apophthegms (1669). B. As adj .: (See the compounds.) compa -bar, s . A fixed iron ring in the silver. from-lead-extracting furnace, which supports the test or cupel-hearth in place in the reverberatory, where the proce is carried on. [SILVER-FROM LEAD-EXTRACTING FURNACE.] ( Knight .)