DYE 



incline to crimson or purple, by adding a 

 small quantity of cochineal or madder. 

 A little tartar gives brightness to the co- 

 lour. With a mixture of galls, fustic, and 

 logwood, some madder, and a little alum, 

 hazel colours are produced. 



Of dyeing Silk dark mixed colours. 



Silk may be dyed a violet purple, with- 

 out a blue ground, by preparing it with 

 a mordant of two ounces of alum, one 

 ounce of solution of tin, and half an ounce 

 of muriatic acid, to each pound*; steeping 

 it twelve hours in a mixture of one part 

 of galls dissolved in white wine, with 

 three parts of water; and then, after 

 wringing, dyeing it in a bath composed 

 with two ounces of cochineal and a small 

 quantity of iron liquor, tiD the intended 

 shade is given. Madder may be used in 

 the same way. 



Colours resembling that of bricks may 

 be produced, by immersing silk in an an- 

 notta bath, after preparing it with a mix- 

 ture of solution of galls and iron liquor. 



By the combination of brazil, logwood, 

 archil, and galls, and by browning with 

 copperas, a number of different shades 

 are dyed : but though their brightness is 

 pleasing, they are not permanent. 



Of dyeing Cotton and Linen dark mixed 

 colours. 



Thread and cotton may be dyed a per- 

 manent violet, by submitting them, after 

 being scoured in the common mode, to 

 a mordant prepared by boiling two quarts 

 of iron liquor with four quarts of water 

 for every pound, carefully removing all 

 the scum, and adding to this liquor pour- 

 ed into a vat, while warm, four ounces of 

 sulphate of copper, and one ounce of nitre 

 to the quantity stated. In this the skeins 

 are steeped ten or twelve hours, wrung 

 out, and dried, and then dyed in a madder 

 bath, if suitable to the shade want- 

 ed. If a deep violet is required, two 

 ounces of verdigris must be added to the 

 bath ; and the colour becomes still deep- 

 er, by galling the yarn more or less before 

 it is steeped in the mordant, if the nitre 

 be omitted. If the proportion of nitre is 

 increased, and the sulphate of copper di- 

 minished, the violet inclines more to lilac. 

 By modifying the mordant in different 

 ways, a number of different shades may 

 be produced. 



To dye cotton different shades of ma- 

 rone colour, it is galled, dipped, and work.* 



DYN 



ed in the usual way in a bath, to which 

 more or less iron liquor has been added. 

 It is then washed in a bath mixed with 

 verdigris, welded and dyed in a bath of 

 fustic, to which a solution of alum and 

 soda are sometimes added: it is then 

 completely washed, after that well mad- 

 dered, then dipped in a weak solution of 

 sulphate of copper, and lastly in soap- 

 suds. 



For some hazels and snuff colours, a 

 browning is sometimes given by soot, 

 after the welding, and a madder bath, 

 to which galls and fustic have been 

 added; the soot is sometimes mixed 

 with the bath : a browning is likewise 

 given by solution of copperas. Walnut 

 peels also are used for the same purpose : 

 the colour they impart is rather dull, but 

 it is not liable to be changed by the air 

 into a yellower shade, as is the case in 

 the brownings imparted by means of iron. 

 The goodness of this dye, and its cheap- 

 ness, are sufficient to recommend its use 

 for grave colours, which are sometimes 

 fashionable. 



For calico printing, see CAI.ICO Print- 

 ing. 



DYNAMICS. This branch of mecha- 

 nics relates to the action of forces that 

 give motion to solid bodies ; which forces 

 are calculated both by their active pow- 

 ers,and by the proportion of time in which 

 those powers become efficient. Our 

 readers cannot fail to perceive, that the 

 complete analysis of all appertaining to 

 this subject would occupy many formi- 

 dable volumes ; while the generality of 

 those who have absolute occasion to ac- 

 quire a complete knowledge of dynamics 

 would be led to consult the various ela- 

 borate publications that have been pub- 

 lished, for the edification of such as pos- 

 sess that disposition. We must, necessa- 

 rily, study simplicity, so far as our sub- 

 ject may admit, and endeavour to bring 

 the most prominent matters into a mode- 

 rate compass. 



Each body is considered as a mass of 

 atoms divisible ad infinitum ; the bulk or 

 substance of a mass we consider as hav- 

 ing density, which relates directly to the 

 quantity of the matter, and inversely re- 

 fers to the magnitude. We are also com- 

 pelled to consider, that, as the generality 

 of bodies are more or less porous, their 

 quantity of matter is not in every instance 

 found to correspond with the bulk they 

 exhibit. Thus we find, that a pound of 

 gold and a pound of lead, though appa- 

 rently spUd, give very different weights 



