CALICO-PKINTING 



613 



fixed on top of cold water pipe exactly opposite pillar, as further shown in fig. 361 

 marked g. Fig. 362 is an end-view of range, with pillar cut, in order to show the 

 position of condense-tap at bottom of pan, and its connection with condense-pipe, and 

 where the point of separation takes place in swivelling, by the line marked h. It 

 will be seen by the foregoing that the process of boiling and cooling is rapid and 

 certain, everything being accurately adjusted and steam-tight throughout the whole 

 apparatus. 



The colours are placed in these pans and stirred well all the time they aro being 

 boiled ; good stirring is very essential to produce smooth colours. This was for- 

 merly done by hand with a flat stick, but lately the best print works have been fitted 

 with machinery over the pans to stir mechanically. A very effective plan of this sort 

 is represented in f.gs. 363 and 364-. It is that of Messrs. Mather and Platt, of Man- 

 chester, the boilers in this drawing being not reversible, though the plan can be just 

 as easily adapted to that description of pans. Fig. 363 is a front elevation ; fig. 364 

 is a transverse section, nndfiff. 365 is a sectional plan, the same letters referring to all. 

 a is a horizontal shaft above the pans, fitted with a pair of mitre wheels, b b, for each 

 pan. The vertical wheel b is not keyed on the shaft a, but is brought into connection 

 with it when required by the catch box c, which slides on a key on the shaft, and 

 revolves with it (see small cuts) ; the catch box is worked by a lever-handle d, and 

 thus motion is given to the vertical shaft e. The shafts a and e are both supported 

 by the framework/, fastened to the wall ; the shaft e is terminated by the frame ghg, 

 the centre of which, h, is a continuation of the shaft e ; and the wings g are hollow to 

 carry the shafts k, which are surmounted by the cog wheels i i, which gear into a cog 



wheel I on the shaft e. The agitators n n are made of flat brass rod, and are curved 

 to fit the bottom ; they are connected with the shafts k k by a hook joint, which is 

 steadied by the conical sliding ring m ; the agitators thus hang from the shaft e, and 

 nearly touch the bottom of the boiler. When the shaft e is put in motion, the 

 agitators have two movements, one round each other, and also each on its own axis ; as 

 they are set at right angles to each other, as shown in fig. 365, it follows that no part 

 of the pan can escape being stirred. When the colour is made, the piece m is slid up 

 on k, and the agitators unhooked and taken out, the waste of colour being very 

 trifling, in consequence of the agitators being outlines only. The saving of labour 

 effected in a colour-house by this machinery is very great, as, after turning-on the 

 steam, the pan may be left to itself till the colour is finished. 



From the great variety of substances used in mordants and colours, of very different 

 chemical properties, a variety of thickening substances is required. Chemical com- 

 bination between the mordants or colour and the thickening substance is to be avoided 

 as much as possible, for such combination may be regarded as so much pure loss, the 

 fibre of the fabric not being able to decompose and assimilate them. Several circum- 

 stances may require the consistence of the thickening to be varied ; such as the nature 

 of the mordant, its density, and its acidity. A strong acid mordant cannot be easily 

 thickened with starch ; but it may be by roasted starch, vulgarly called British gum, 

 and by gum arabic or Senegal. Some mordants which seem sufficiently inspissated 

 with starch, liquefy in the course of a few days ; and being npt to run in the printing- 

 on make blotted work. In France, this evil is readily obviated, by adding one ounce 

 of spirits of wine to half a gallon of colour. 



The very same mordant, when inspissated to different degrees, produces different 

 tints in the dye-copper ; thus, the same mordant, thickened with starch, furnishes a 

 darker shade than when thickened with gum. Yet there are circumstances in which 



