T R A 



daces a florid red. Many other red flowers hardly gire any 

 colour to fpirit of wine in a (hort time, yet give a red colow 

 by the addition of any of the acids. A folution of mercury 

 aad oil of tartar gives orange ; a folution of fublimate and 

 lime-water produces yellow. The tinfture of red rofes 

 with oil of tartar per deliquium, or with fpirit of fal am- 

 moniac, gives green. In like manner, the tinftm^ of many 

 red flowers it changes into green by an alkali. The tincture 

 of red rofes and fpirit of wine gives blue. The folution of 

 copper and fpirit of fal ammoniac gives purple. The folu- 

 tion of fablimate and fpirit of fal ammoniac gives white. 

 The folution of faccharum fatumi and that of vitriol, alfo 

 the tjndure of red rofes, or many other red flowers, and the 

 folution of copperas in water, and likewife the fohition of 

 gsdls and copperas, produce black. The following table 

 exhibits the colours arifing firom different mixtures. 



Tinaure of red rofes 



Tindure of crocus 



Tindare of violets 



Spirit of fulphur 



Tincture of red rofes 



Spirit of hartfcom 



Tinfture of violets 



Solution of copper 



TinSure of violets 



Solution of Hungarian vitriol 



Ticctare of cyanus 



Spirit of fal ammoniac 



Solution of Himgarian vitriol 



Lixivium 



Solution 01 Hungarian vitnol 



TicAure of red rofes 



Ticaure of cyaaas 



Scrfution of copper 



Tincture of dipfacitBi, or iris, 

 anv other flowers that eive 

 violet colour in water 



Alum diffolved in water. 



Pradace 

 green. 



-green, 

 yellow. 



Hblu. 



Mufchenbroeck's Introd. ad Phil. Nat. torn. ii. p. 738, 

 &c. The refult of a variety of mixtures to produce coloiirs, 

 was recited before the Royal Society by Dr. Goddard in 

 1661, and may be feen in Birch's Hiftory, vol. i. p. 11. 



Mr. MelviUe has made many obfervations on the tranf- 

 mutation of colours by means of the light of different 

 burning bodies. Bodies of all the principal colours, Tta. 

 red, yellow, green, and blue, are very little altered, he ob- 

 tierves, when they are feen by the light of burning fpirits ; 

 but if falts be continually mised with them, during the 

 burning, different changes enfue. When fai ammoniac, 

 pota/h, or alum, are infiifed, the colour of red bodies appears 

 fomewhat faded and dirty. Green and blue appear much 

 Ae (ame as in candle-light, both being faint, and hardly dif- 

 tingmihable. White and yellow are hardly at all affeded. 



'When EJtre, or fez-isk, is plentifiilly mixed with the 

 burning fpirits, and the whole is flirred about brifldy, the 

 brighteft red bodies, feen by the light then emitted, are re- 

 duced to a dirty tawnv brown, which feems to have nothing 

 of tedaefs in it. Green is transformed into another fort of 

 brown, only diftingniftiable from the former by a certain in- 

 clination to a livid oKve colour. When nitre is mixed with 

 the fpirits, one may ftiH fee fome remains of greenifh colour, 

 uolefs it -be poured in very plentifuDy. Dark blue is hardly 

 to be known from black, except that it appears tte deeper 

 black of the two. Lig^t blue is changed into a very tght 



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brown, of a peculiar kind. Ti^Tiite affumes a livid yellow-- 

 iih caft ; and yellow alone appears unaltered, and extren-.elv 

 luminous. 



Thefe experiments he made with different forts of richly 

 coloured bodies, as filks, cloths, and paints. PoUflied cop- 

 per, which had contracted from the air a high flaming 

 colour, was reduced, by the fame light, to the appearance 

 of vellow brafs. The faces and hands of the fpefiators 

 appeared like thofe of a dead corpfe ; and other mixed co- 

 lours, which had red or green in their compofition, under- 

 went the like changes. 



Having placed a pafteboard, with a circular hole in it, 

 between his eve and the flame of the fpirits, in order to di- 

 minifli and circumfcribe this objed, he examined the confH- 

 tution of thofe different hghts with a prifm, holding the 

 refraoing angle upwards : and found that, in the firft cafe, 

 TJs. when &1 ammoniac, alum, or potafti fell into the fpirits, 

 rays of all kinds were emitted, but cot in equal quantities, 

 the vellow being much more copious than all the reft put 

 together, and the red bang more faint than the green and 

 blue. 



In the light of fpirit* mixed with nitre, or fea-falt, be 

 could obferve fome blue, though exceedingly weak and di- 

 luted. With the latter the green was equally faint, but 

 with the former prettv copious. But when either of thefe 

 falts was ufed, he could hardly perceive any trace of red. 

 efpecially when they were mixed in great plenty, and the 

 fpirits conftantly agitated. At every little intennifGon, in- 

 deed, the red rays would fliew themfelves verv manifeftly 

 below the hole, and red bodies feen by that hght refumec 

 fomswhat of their ordinary colour ; and it was entertaining 

 to obferve how both would vanifh again at once, when the 

 falling and ftirring were renewed. 



The proportion in which the bright yellow exceeded the 

 other colours in this light, was ftill more extraordinary than 

 in the former : infomuch that the hole, feen through the 

 prifin, appeared uniformly of that yeUow, and as diftinftly 

 terminated as through a plane glafs ; except that there was 

 adjoining to it, on the upper fide, a very faint ib-eak o: 

 green and blue. White bodies illuminated with it, appeared 

 alfo through the priCm perfectly well defined, both which, 

 he favs, are very furprifing phenomena to thofe who have 

 been accuftomed to the ufe of the prifm in heteroger.eou= 

 hghts, where it never fails to throw confuiion on the ex- 

 tremities of all vifible objeds. ] 



Upon examining bubbles of foap and water in the fame 

 Kght, he cotdd only obferve luminous ftreaks, feparated by 

 dark ones, the green and blue being too weak to affeft his 

 eye. Edinb. Effays, vol. ii. p. 32. 



Traxsmvtatiox of Plants. See Seeds and Degexe- 



RATIOX. 



TRANSOM, among BmUers, the piece that is framed 

 acrols a double light window. 



Transom, among MathcToaticunu, denote? the vane of a 

 crofc-ilaff; or a wooden member fixed acrofs it, with a 

 fquare whereon it Aides, &c. 



Traxjoms, in a Ship, are beams and timbers extended 

 atxofs the ftem-poil of z fliip, to fortify her after-part, and 

 give it the figure moft fuitable to the fervice for which fhe 

 is calculated. See Ship-buildi.vg. 



The general figure or curve given to the fhip by the dii- 

 pofiticn of the arms of the tranfoms, which are gradually 

 dofer in proportion to their diftance firom the wing-tranfom 

 downwards, in confequence of which it becomes extremely 

 narrow from the counter towards the keel, is called the fi:jlx 

 of the traafoms. Although thefe pieces are estremelv dif- 

 ferent in their Sgrires, according to the extent of the angles 



fcnned 



