REF 



HEP 



Mik, cotton, &c. Reeling 1 is performed 

 different ways, and on different engines. 



RE-ENTRY, in law, signifies the re- 

 suming or retaking a possession in land 

 lately lost. 



REFERENCE, in law, is where a mat- 

 ter is referred by the Court of Chancery 

 to a master, and by the courts at law to 

 a prothonotary, or secondary, to examine 

 and report to the court. Reference also 

 signifies where a matter in dispute is re- 

 ferred to the decision of an arbitrator. 

 This is done either by parol agreement, 

 or by bond, or upon a suit, in which lat- 

 ter case the party has a rule of court, that 

 the party against whom the award Is made 

 shall perform it, and then he may move 

 to have an attachment against him if he 

 does not perform it. By statute also this 

 may be done, where the parlies agree 

 that the award should be made a rule of 

 court, although there is no suit. 



REFINING. See ASSAYING. 



REFLECTING circle, an astronomical 

 instrument for measuring angleSj It is 

 called reflecting from its property, in com- 

 mon with the Hudley's quadrant (of which 

 it is a modification) of observing one of 

 the objects of the angle to be measured 

 by distinct vision, and the other by re- 

 flection of plane mirrors. The first in. 

 strument of this kind was invented by 

 Tobias Mayers, in 1770, a celebrated 

 astronomer of Gottingen, who calculated 

 the lunar and solar tables for determining 

 the longiiude at sea, for which a reward 

 of 3,000/. was given by the board of lon- 

 gitude,. In making use of these tables 

 he found that the Hadley's quadrants, 

 though made by the first artists of that 

 time, were not divided with sufficient ac- 

 curacy for his purpose ; he therefore con- 

 trived the reflecting and repeating circle ; 

 to comprehend which, the reader must 

 turn to our article QUADRANT, by Had- 

 ley, from which this instrument differs, 

 principally, in being a whole circle of di- 

 visions instead of an octant ; and is so 

 contrived, that when an observation has 

 been made, it is repeated upon a fresh 

 portion of the divisions, then a third 

 time, a fourth, and so on as many times 

 as is necessary ; the observation is then 

 read off, and the product is divided by 

 the number of observations, made so as 

 to take a mean of the errors there may 

 be in any part of the divisions on the 

 circle. This contrivance, though useful, 

 was found so tedious, in taking so many 

 observations, that it was laid aside in 

 favour of the Hadley's quadrant, to which 

 in point of accuracy it was really superior, 



For the particular description of this 

 instrument we must refer our readers to 

 a work, entitled, " Tabula Motum Solis 

 et Lunx," by Tobias Mayer, London, 

 1770. This instrument received an im- 

 provement from the Chevalier de Borda, 

 at Paris, which rendered its operation 

 much more simple ; but it was not until 

 the year 1796 that the instrument became 

 much used in the British navy, when it 

 was new modelled by Mr. Edward 

 Troughton, and the objections to the 

 former instruments done away. We have 

 obtained permission from this gentleman 

 to make a drawing of this instrument 

 (see Plate Reflecting Circle) where (fig. 

 1.) is a plan of the divided side of the in- 

 strument, (and fig. 2) a perspective view 

 of its upper side. A A, in both figures, is 

 a circle of brass, with a narrow ring of 

 silver let into a circular groove in it, as 

 is seen in fig. 1, on which silver the divi. 

 sions are made. B B B are three arms 

 carrying verniers at their ends, they are 

 all cast in one piece, and screwed to a 

 truly turned steel axis, fitting into a tube, 

 which is screwed to the centre of the 

 circle (this tube cannot be seen in the 

 plan, but is denoted by a in fig. 2) the in- 

 dex glass, If, which is a plane silvered 

 mirror, is fastened to the other end of 

 this axis by three screws, in such a posi- 

 tion that the centre line of the steel axis 

 it is fixed to, if produced, would exactly 

 coincide with the plane of the silvered 

 surface of the mirror, and consequently 

 that the plane of the mirror produced 

 passes through the centre of the circle 

 A A, perpendicular to its plane. 



To the upper end of the tube, a (fig. 2) 

 a crooked plate of brass, tf d, is fastened, 

 and connects it with two other tubes, e and 

 f, whose lower ends are fixed to the cross 

 bar frame of the circle ; one of these, /, 

 has the mirror, /i, called the object glass 

 placed on it ; the other has a telescope, 

 ky fixed to it, directed to the object glass, 

 h. The instrument is held, when in use, 

 by handles adapted to different occasions, 

 of which there are four ; two perpendicu- 

 lar and two parallel to the plane of the 

 circle ; of the latter, e, is one on the up- 

 per side, supported by a small pillar 

 coming from the interception of two of 

 the bars of the frame, and steadied by 

 entering the tube ; a, the other handle is 

 at the divided side of the circle, and is 

 fastened to the circle at the upper side s 

 in the same manner as e t by a crooked 

 hollow tube, G, going round the circle ; 

 of the other two handles, one, m, is above 

 tUe circle, screwed into a cock fixed to 





