IMPROVEMENTS IN TANNING. 271 



There is no part of carpentry that requires greater correctness 

 in workmanship than scarfing ; as all the indents should bear equal- 

 ly, otherwise the greater part of the strength will be lost. Hence 

 we see how very unfit some of the complicated forms shown in the 

 old works on carpentry were for the purpose. It is certainly very 

 absurd to render the parts diflicult to be fitted, when the whole of 

 the strength depends on their fitting well. " But many," says Pro- 

 fessor Robison, " seem to aim at making the beam stronger than if 

 it were one piece ; and this inconsiderate project has given rise to 

 many whimsical modes of tabling and scarfing." 



ENGLISH PATENTS. 



To Thomas John Knowlys, Esq. and William Duesburv, Color 



IMannfacturer, for their havuig invented certain improvements in 

 Tanning. Enrolled February, 1827. 



This improved mode of tanning, consists in suspending the hides 

 in a close vessel, from the interior of which the air is to be ex- 

 hausted by means of an air-pump, and when the \acuum within 

 is sufficiently perfect, the tanning liquor is admitted, which imme- 

 diately penetrates into the pores of the hide, occupying the place 

 from whence the air has bfen extracted. By these means the 

 operation of tanning will be greatly facilitated. 



The hides to be tanned, are introduced into the vessel, and are 

 suspended by hooks at the upper corners, with weighfs at botlom 

 to keep the skin extended. As many of these hides as may be re- 

 quired to he tanned, are in this way placed within the vessel, and 

 when the lid is tightly fixed on, the air is to be extracted from the 

 interior by means of an air-pump. 



When a sufficient exhaustion has beesi etiected within the vessel, 

 the cock of <he air-pump is to be closed, and another opened, and 

 the tanning liquor introduced ; after which, the air-pump may be 

 again worked to draw all the air from the pores of the skins ; and 

 to prevent ebullition, a quantity of oil is to be placed upon the sur- 

 face of the tanning liquor. 



The tanning liquor is to be first used in a weak state, and its 

 strength increased daily, until the process is complete. A puitip 

 and tube, are to be employed for drawing off the spent tan liquor. 



The subject of this patent is an example of the wide range through 

 which a valuable hint may be sometimes usefully extended. In the 

 second volume of our first series, page 36, will be found a commu- 

 nication from John Oldham, Esq. of the Bank of Ireland, on his 

 improved method of sizing, dying and wetting paper, for printing 

 Bank Notes, and other purposes, which process was, by placing the 

 bundle of papers, in a close vessel, and after exhausting the air from 

 the vessel, and, consequently, from the pores of the paper, intro- 

 ducing the size dye or water, which instantly penetrated the paper. 



