CZ DireSlons for Towilng 



tain fuch fahnances as contain the gallic principle. Litne 

 walerwill al ft)- produce ihis elt^^. 



When tile Ui^uor oeafes to grow black by the;mixture of 

 ttie fulphate oPiron, it will be ufekifs to pour any more water 

 on the tan in the iirft digefler. This tan, being exhaufted 

 bo;h of the tajnn'ig and gillie principles, mull be removed, 

 aud iieW- tan put in its place. 



3. You will obferve that the liquor, after nmning through 

 all the digelUrs, at lad grows weak. Add to your ftock of 

 tanning lixivium all the liquor that marks from fix to eight 

 degrees on the h\'dronieler. What proceeds afterwards ficmi 

 the laft di(:elter is.to be poured on the new, fan in the firft. 

 Then the frefli water is to be conveyed on the tjn in th-e 

 fecond digelt^r, and the liquor of the firft to be laid by, u;hile 

 it marks fix or eight degrees on the hydron cier, and atlded 

 to the tanning lixivium, which muft ahva\s be carefully fe- 

 parated from tlie gailic. In this manner, the tan ip all the 

 digefters may be renewed, and the lixiuations contiuued. 



The number of thefe Jixiviatiqns, as well asihe mode of 

 making them, may be varied at pleafure; the eCTential point 

 is to repeat them fo as to give the liquor a fufficient degree 

 of concentrali'in, vi'hich may be determined by the hydro- 

 meter, and proportioned to the quick nefs required in the 

 operation, and the thicknefs of the hides and fkjns to be 

 taniMid ; all which experience will foini teach. As j^lJ kinds 

 of tau are not equally good, it will fometimes iiappen that 

 fiK or more fiUrations will be neceflary to obtain a lixivaim 

 of fix or eiglu degrees : in this cafe, as wel4 a« where a greater 

 quantity of liquor is require*.!, the number of digcfters is to 

 be increafed, gad, the fame method purfued as above j; and 

 when a weaker Jixivium is vyaiued, thre^ or foyr fiUraiipng 

 will be fufficient. , ' , , . . 



The perfoa who direfts thpf^ Vxiyiations fhou^ be pro- 

 vided with the folution of (ilue and f^dphate of iron, already 

 tlercrihed, in order to afcertain the qualities of the different 

 lixivia, as well as with a hydrometer or areometer, properly 

 graduated, to delermiiie their degree of coJiceiUration or fpe- 

 cific gravity. 



Cow Hides, Ox H'ldeSy ^c. 



1. Wojhhig and FIc/l lag. —They fiiould be watlicd ia 

 running water, well cleaned, and fle(hed in the ufual way. 



2. Dt-pilatio7i, or, taking o^' the H^ir.-^f ninitrijc the hides 

 for two or three days in a vat filled with the gallic lixivium, 

 and a mixlireof fulphuric acid, or oil of vitriol, marking 

 66 degrees on the hydrometer for acids, and in the propor- 



6 \ ji tioA 



