RED 



REE 



strongly to the tongue; feels meagre; 

 specific gravity 3.9. Exposed to a red 

 heat, it decrepitates, and becomes black ; 

 it may even be melted into a greenish 

 grey spumous enamel. In Silesia it is 

 found in compact limestone . it is princi- 

 pally used for drawing : the coarser kinds 

 are used by the carpenter, the finer by 

 the painter. It is sometimes used in its 

 natural state, and sometimes pulverized, 

 washed, and mixed with gum, and cast 

 into moulds. 



REDEMPTION, and EQ.TJITT of Re- 

 demption, in law. See MORTGAGE. 



REDOUBT, in fortification, a square 

 work raised without the glacis of the 

 place, about musket-shot from the town ; 

 having loop-holes for the small arms to 

 fire through, and surrounded by a ditch. 

 Sometimes they are of earth, having only 

 a defence in front, surrounded by a para- 

 pet and ditch. Both the one and the 

 other serve for detached guards to inter- 

 rupt the enemy's works ; and are some- 

 times made on the angles of the trenches, 

 for covering the \voi'kmen againt the sal- 

 lies of the garrison. The length of their 

 sides may be about twenty fathoms : their 

 parapets must have two or three ban- 

 quettes, and be about nine or ten feet 

 thick. They are sometimes (in a siege) 

 called places of arms. 



REDUCTION of metals, in chemistry. 

 All metals, even the few that resist the 

 action of heat and air, undergo a similar 

 change when exposed to acids, especially 

 the sulphuric, the nitric, and the muria- 

 tic, or a mixture of the two last. All 

 metals, by these means, may be convert- 

 ed into powders, which have no resem- 

 blance to the metals from which they 

 were obtained. These powders were for- 

 merly called calces ; but at present they 

 are better known by the name of oxides. 

 They are of various colours, according 

 to the metal and the treatment, and are 

 frequently manufactured in large quanti- 

 ties, to serve as paints. When these oxides 

 are mixed with charcoal powder, and 

 heated in a crucible, they lose their earthy 

 appearance, and are changed again into 

 the metals from which they were pro- 

 duced. Oil, tallow, hydrogen gas, and 

 other combustible bodies, may be often 

 substituted for charcoal. By this opera- 

 tion, which is called the reduction of the 

 oxides, the combustible is diminished, and 

 indeed undergoes the very same change 

 as when it is burnt. In the language of 

 Stall), it loses its phlogiston ; and this 

 induced him to conclude that metals are 

 composed of earth and phlogiston. Mr. 



Davy, as we have seen in other parts of 

 this work, inclines to the opinion that 

 there are only two principles in nature, 

 an inflammable and metallic principle. 



REDUCTION. See ARITHMETIC. 



REDUCTION of a figure, design, cw 

 draught, is the making a copy thereof, 

 either larger or smaller than the original ; 

 still preserving the form and proportion. 

 The great use of the proportional com- 

 passes is the reduction of figures, &c. 

 whence they are called compasses of re- 

 duction. There are various methods of 

 reducing figures, the most easy is by 

 means of the pentagraph, or parallelo- 

 gram ; but this has its detects. See PEN- 

 TAGHAPII. 



REE, REIS, or RES, a little Portuguese- 

 copper coin. 



REED, an ancient Jewish measure. See 

 MEASURE. 



REED, or the Common REED, in botany. 

 arundo. See ARUNDO. 



REEF, a term in navigation. When 

 there is a great gale of wind, they com- 

 monly roll up part of the sail below, that 

 by this means it may become the narrow- 

 er, and not draw so much wind ; which 

 contracting or taking up the sail they call 

 a reef, or reefing the sail : so also when a 

 top-mast is sprung, as they call it, that 

 is, when it is cracked, or almost broken 

 in the cap, they cut off' the lower piece 

 that was nearly broken off', and setting 

 the other part, now much shorter, in the 

 step again, they call it a reefed topmast. 

 The term " reef' implies also a chain of 

 rocks lying near the surface of the water. 



REEL, in the manufactories, a machine 

 serving for the office of reeling. There 

 are various kinds of reels, some very sim- 

 ple, others very complex. Of the former 

 kinds those most in use are, 1. A little 

 reel held in the hand, consisting of three 

 pieces of wood, the biggest and longest 

 whereof (which does not exceed a foot 

 and a half in length, and one-fourth of an 

 inch in diameter) is traversed by two 

 other pieces disposed different ways. 2. 

 The common reel, or windlass, which 

 turns upon a pivot, and has four flights 

 traversed by long pins or slicks, whereon 

 the skein to be reeled is put, and which 

 are drawn closer or opened wider, accord- 

 ing to the skein. 



REELING, in the manufactories, the 

 winding of thread, silk, cotton, or the 

 like, into a skein, or upon a bottom, to 

 prevent its entangling. It is also used 

 for the charging or discharging of bob- 

 bins or quills, to use them in the manu- 

 facture of different stuffs, as thread* 



