An essay on the culture and manufacture of indigo : to which was awarded the prize of eight hundred rupees by the Madras Government, 1860 / by John Shortt.

  • Shortt, John.
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: An essay on the culture and manufacture of indigo : to which was awarded the prize of eight hundred rupees by the Madras Government, 1860 / by John Shortt. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    with advantage as it facilitates the process. The top of the frame is to have a board let in containing the factory mark, so that while the cakes are being cut into squares, a little additional force will also mark them, and both the operations of cutting and stamping might go on at one and the same time. Some breakage will of course occur, but if a cake break it should be slightly wetted and the pieces brought together by a little force, which will cause the fragments to adhere. The practice often resorted to of breaking up the cakes to have them submitted to the press-box a second time, is objectionable as it deteriorates the dye. The cakes having been cut and stamped, should now be placed on a tray with a double layer of stout coarse cloth having a layer of good bibulous paper between. The common unsized country paper answers the purpose very well. On the frame thus prepared the cakes should be gently and carefully laid, about 3 inches apart. The tray should then be removed to the drying house, and there be placed in a loft where it should remain for some three or four days, after which the cakes should be as carefully removed on to the stages in the drying house, observing the same interval of space as was given when they were placed on the tray. The stages may be formed of wood or bamboo. The cakes will retain their sugary smell for some days, unless something has gone wrong in the manufacture, such as excess or insufficiency in boiling. The cakes when drying, should never on any account be turned, for this drives the moisture from the surface to the centre. The drying house should be capacious, airy, and well lighted, for if not so, the white coat which the cakes of Indigo acquire from the growth of fungi upon them, will not occur ; as it is well known that light is essentially necessary for the growth of these fungi; and it being desirable that the cakes should be as sound as possible, their growth should be encouraged by the free admission of light and air. When the Indigo is dry, each day’s manufacture is taken up and cleaned with a very soft brush. Soft brushes are best, because bard brushes remove'the white fungus covering the cakes, and thus take away from their appearance and value. The cakes are now carefully compared and arranged, after breaking off the edge 'of one side of a cake for the purpose of'exhibiting its inner surface. They are then packed, and in doing so. a sample cake is generally kept,