VOL. LXVIII.] PHILOSOPHICAL TRANSACTIONS. 307 



that in the ordinary course of business, and in a common tan-yard, the tanner 

 may save at least 4 months out of 12, produce better leather, and find his bark 

 go much further, than in the old way of tanning. 



Instructions to Tanners, for carrying on the new method of tanning, invented by 

 Dr. Macbride, of Dublin ; by ivhich the leather is not only improved in its quality, 

 but tanned in much less time, and with a smaller quantity of bark, than in any 

 other method hitherto known or practised. — As the new method of tanning depends 

 on this principle, " That lime-water extracts the virtues of oak-bark more com- 

 pletely than plain water;" the first thmg in which the tanner is to be instructed, 

 is the making of lime-water. I . Provide a large vessel, in the nature of a cistern, 

 whose depth shall be at least twice its diameter, and of a capacity adapted to the 

 extent of the tan-yard. '2. This cistern must be fixed in a convenient corner 

 of the yard, under a shed, and should stand so as that the liquor to be drawn off 

 from it may run freely into the letches. 3. There must be a cock fixed in the 

 side of the cistern, about a foot from the bottom, to let oft" the contents; and 

 there must be a hole in the bottom of it, of 5 or 6 inches diameter, which 

 is to be stopped with a plug. Let this hole open over a gutter. 4. The cistern 

 must be covered with a flooring of boards, strong enough to bear a man's 

 weight; and from side to side of this lid there must be an opening of 2 or 3 

 feet wide. 5. If it can be so contrived that a water-pipe may be led into the 

 cistern, it will save the servants a good deal of trouble; but if this cannot be 

 done, a pump must be fixed in the most convenient way, for the purpose of 

 filling it from time to time. 6. The cistern being once fixed (which is all the 

 additional apparatus that the new method of tanning requires) the making of 

 lime-water will be found extremely simple and easy. 7. You are first to fill the 

 cistern with water, and then, for every hogshead that it may contain, throw in 

 10 or 12 lb. weight of unslaked lime. 8. Mix the lime thoroughly with the 

 whole body of the water, by stirring it exceedingly well from the bottom, with 

 a bucket and plunger, till you perceive that the lime is completely diffused, and 

 the whole mixture becomes as white as milk: leave it then to settle for a couple 

 of days, that the undissolved part of the lime may entirely subside, and the 

 water become perfectly limpid, and clear as rock-water. The lime-water will 

 then be fit for immediate use. 



9. The cock, as already mentioned, is to be fixed at least 12 inches from the 

 bottom of the cistern, in order that only the limpid part of the lime watei may 

 run off"; and the use of the hole in the bottom, which is ordered to be stopped 

 with a plug, is to let off" the gross and insoluble remains of the lime, as often as 

 may be found necessary to clean out the cistern. 10. When the first brewing 

 (as it may be termed) of lime-water is all expended, you are to fill up the cistern 

 with water a 2d time; stir up the lime from the bottom with the bucket and 



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