726 



DECOCTION 



DECORATED STYLE 



attached to the axis of the telescope, on which is 

 hung the level L, for adjusting the instrument 

 previous to making an observation. Inside the 

 compass-box is another graduated circle F, the line 

 joining the zero-points of which is parallel to the 

 axis or the telescope. The compass-box and tele- 

 scope thus move round together on an axis passing 

 through the centre of the azimuthal circle. When 

 an observation is made, the instrument is first of 

 all levelled, and the telescope directed to a star 

 which is either on the astronomical meridian or 

 whose position with respect to it is known. The 

 reading of the inner circle then gives the declina- 

 tion at once, in the former case ; if the latter i.e. 

 if the star be not on the meridian, the reading of 

 the inner circle has to be corrected by adding or 

 subtracting, as the case may be, the position of 

 the star in azimuth, in order to give the declina- 

 tion. In order to obviate error due to the non- 

 coincidence of the magnetic and geometric axes of 

 the needle, a second reading is taken with the face 

 of the needle reversed ; the mean of the two read- 

 ings is taken as the true declination. 



It is found, however, that this instrument only 

 gives results approximately correct, and has in 

 consequence been superseded in observatories and 

 magnetic surveys by a form of the unifilar magnet- 

 ometer. For an account of the determination of 

 declination by this latter instrument, see MAGNET- 

 OMETER. Details as to the value and secular change 

 of the declination at different places on the earth's 

 surface will be found under MAGNETISM. 



Decoction, the term applied in pharmacy to 

 the solution procured by boiling an organic sub- 

 stance with water. 



Decolorim'eter, an instrument for determin- 

 ing the power of portions of bone-black or animal 

 charcoal to abstract colouring matter. See CHAR- 

 COAL. 



Decomposition is the rather comprehensive 

 term applied to' the breaking up of complex sub- 

 stances, or substances of delicate stability, into 

 others which are less complex or more stable. 

 Such breaking up is very familiar in many chemical 

 changes, and may result from increase of tempera- 

 ture, the action of light, the action of ferments and 

 micro-organisms, and so on. The ordinary process 

 of alcoholic fermentation is a good example of 

 decomposition, which takes place in the presence 

 of, and is dependent upon, the life and growth of 

 yeast in the saccharine solution. Similarly the 

 oxidation of nitrogenous 'organic matters with 

 formation of nitrates, if not dependent upon, is 

 greatly accelerated by the presence of a micro- 

 organism. 



The term decomposition is constantly applied in 

 chemistry to the changes which compounds undergo 

 in the most varied circumstances when subjected 

 to change of conditions. See also CHEMISTRY, 

 FERMENTATION, PUTREFACTION. 



Decomposition of Forces. See COMPOSI- 

 TION. 



Decorated Style of Gothic Architecture. 

 This style prevailed in England during the reigns 

 of the first three Edwards, or from towards the 

 close of the 13th till near the end of the 14th 

 century. Under GOTHIC ARCHITECTURE it will be 

 shown how the pointed style progressed, and was 

 naturally and logically developed in all its elements, 

 constructional as well as decorative, until skill 

 in execution exceeded originality in design, after 

 which the art gradually deteriorated. The Decor- 

 ated or second pointed style occupies the position 

 'in which these two elements were in full r s^rd and 

 completest development. Hence this isie^ variably 

 considered the perfect period of Gothic Architecture. 

 In the Decorated style the simple forms of the 



early pointed became more complex. The simple 

 roll is divided into two parts, the mouldings are 

 more numerous and refined, and they are beauti- 

 fully grouped and proportioned. The pillars con- 

 sist similarly of clustered shafts or mouldings 

 arranged commonly on a lozenge plan ( fig. 1 ). The 

 caps are usually carved in imitation of natural 

 foliage, and partake of the character of wreaths 

 growing round the caps, instead of springing from 

 the neck-rnoulding as in the preceding style (fig. 

 2). The buttresses are encircled with niches and 



Fig. 1. Column, Col- Fig. 2. Decorated Capital, 

 legiate Church, Man- York Cathedral. 



Chester, 14th century. 



canopies, and the latter are more elaborately 

 decorated than formerly. The drip-mouldings over 

 doors, windows, niches, &c. are crocketed and 

 formed into an ogee curve at the top, and 

 finished with a finial in short, every detail is 

 elaborated and richly decorated. But this develop- 

 ment is most prominently marked in the tracery of 

 the windows. In the first pointed style this feature 

 is of the simplest character ; but in the Decorated 



Fig. 3. Niche, Wai- Fig. 4. Window, Broughton, 

 pole St Andrews, Oxfordshire, 1300. 



Norfolk, 14th cen- 

 tury. 



it becomes fully developed, and forms the most 

 prominent characteristic of the style. At first 

 the tracery consists of geometric figures, such as 

 circles, trefoils, &c. ; but in the later examples it 

 develops into flowing lines, which in France passed 

 into the 'Flamboyant' (q.v.). This development 

 of the tracery le*d to the enlargement of the 

 windows, in order to afford, space for its exhibi- 

 tion. Large circular windows, filled with tracery, 

 were also introduced (see WINDOW). The early 



