REG 



REG 



3. Refraction, terrestrial and celestial. 

 In astronomical and meteorological ob- 

 servations it is found that every differ- 

 ence of level, accompanied, as it must 

 be, with a difference of density in the 

 aerial strata, must also have, correspond- 

 ing to it, a certain amount of refraction. 

 That which occurs between terrestrial 

 stations is termed terrestrial refraction, 

 to distinguish it from that total effect 

 •which is produced only on celestial ob- 

 jects, or such as are beyond the atmo- 

 sphere, and which is called astronomical 

 or celestial refraction. 



4. Refracting microscopes and telescopes 

 are such as show a magnified image of 

 an object, by means of rays of light re- 

 fracted and collected into a focus through 

 lenses. 



REFRANGIBFLITY {refrango, to 

 break back). The property by which a ray 

 of light admits of being refracted. The 

 term is employed to designate the degree 

 of this property which is possessed by 

 the several divisions of a ray of light. 

 It is owing to their .various refrangibi- 

 lities that the rays separate from each 

 other in passing through the prism, 

 thereby exhibiting the phenomenon of 

 the coloured spectrum. 



REFRIGERA'TION {refrigero, to 

 cool). The operation of cooling a body ; 

 also the condition of a body which has 

 been cooled. A refrigeratory is a chemical 

 vessel filled with water, for the purpose 

 of condensing vapours, or for cooling any 

 substance as it passes through it. 



REGMA (pr](Ta(a, to break). Capsula 

 tricocca. A fruit, consisting of three or 

 more cells, each of which bursts from the 

 axis with elasticity into two valves, as 

 in Euphorbia. The cells of this kind of 

 fruit are called cocci. 



REGULAR BODIES. A term ap- 

 plied to the five regular geometrical 

 solids, viz. the tetrahedron, the hexa- 

 hedron, the octahedron, the dodecahe- 

 dron, and the icosahedron; these are 

 bounded by like, equal, and regular 

 plane figures, and their solid angles are 

 all equal. They were described by 

 Plato, and are hence called Platonic 

 bodies. 



REGULAR FIGURES. These are 

 equilateral and equiangular polygons. 

 About and within such figures circles 

 can be described. 



RE'GULARS. In chronology, there 

 are two kinds of Regulars, the solar and 

 the lunar. 



1. The Solar Regulars are fixed num- 



bers attached to each month. The regu- 

 lar for— 



The Regulars are used with the Con- 

 currents in ascertaining on what day of 

 the week the first day of each month fell. 

 The Regulars of the month being added 

 to the Concurrent of the year, the sum, 

 if it does not exceed 7, shows the day of 

 the week required, 1 representing Sun- 

 day, 2 Monday, and so on. If it exceed 

 7, that number is to be subtracted, and 

 the remainder shows on what day of the 

 week the first day of each month in that 

 year fell. Thus, if the day of the week 

 of the 1st December, 1272, be required: 

 Regular of December (7) + Concurrent 

 of A. D. 1272 (5) =12. Subtract 7, and 

 the remainder, 5, denotes the 5th day of 

 the week, or Thursday. 



2. The Lunar Regulars consist also of 

 a fixed number assigned to each month 

 of the year. By adding thereto the 

 Epact, the age of the moon on the first 

 day of each month is ascertained. The 

 following is a table of the Lunar Regu- 

 lars, according to the calculations of 

 those who began the year in January or 

 March : — 



If the lunar year commenced in the 

 month of September, as with the Egyp- 

 tians, and four months before the Julian 

 year, the Lunar Regulars for September 

 and October are 5, and for November and 

 December 7 ; but for all the other months, 

 the numbers are those in the preceding 

 table. 



By adding the Lunar Regulars to the 

 Concurrent of any particular year, the 

 day of the week is shown on which the 

 first day of the Paschal moon fell. If the 

 sum does not exceed 7, the day following 

 was the first of the Paschal moon ; if the 

 Lunar Regulars and Concurrent exceed 



