9 



4th. If the salts be mixed in the proportion of Tinctura 

 Acetatis ferri cum Alcohol, Pharni. Dub. and distilled wateu 

 used instead of Alcohol, the liquor is at first clear, but on 

 standing for some hours it becomes turbid, and at length 

 thickens so as to resemble a jelly. If it be then diluted with 

 an equal quantity of water, it deposits the oxyd copiously ; 

 The supernatant liquor reddens Litmus paper strongly. 



Hence we may explain why, bj'^ increasing the proportion 

 of the acetate of Kali, which has a strong attraction for water, 

 so as to leave this salt superabundant, the tincture in rectified 

 spirit becomes permanent; the water of the rectified spirit 

 being engaged with the salt, is prevented from acting upon 

 the acetic acid of the acetate of Iron, and thus separating it 

 from the oXyd. 



An acetate of Iron may be directly procured by digesting 

 precipitated Carbonate of Iron with acetic acid. The solu- 

 tion is of a deep crimson colour. Although the acid be di- 

 gested, for several days, with more carbonate than it will dis- 

 solve, the liquor is still acid. Hence it is not subject to de- 

 composition when mixed with water. I have also mixed it 

 with rectified or even proof spirit, and the mixtures have re- 

 tained their transparency for several months. 



The acetate of Iron is decomposed by heat; acetic acid 

 may therefore be procured by distilling a mixture of equal 

 weights of acetate of Kali and sulphat of Iron ; the salts, 

 when mixed deliquesce so as to render it difficult to 

 charge the retort; but by adding sulphat of Kali, reduced t;o 

 powder in sufficient quantity, the mass acquires consisteiKJe, 



VOL. XI. c and 



