of Oxalic Acid and of Mercury. 169 



crystals were deposited. Being afterwards reduced on a water- 

 bath, and set aside to dry away, it left prisms like the second 

 crop of (a). None of these crystals were deliquescent. Those 

 produced by spontaneous evaporation readily dissolved quite 

 clear in a small quantity of warm distilled water, and gave the 

 characteristic orange-yellow with solution of potash. The 

 prisms and foUicules dissolved still more freely in their own 

 weight of cold water ; but left a white sediment, which was 

 quickly taken up by a drop of acetic acid. The latter crystals 

 retain their acid with great energy, giving, whether imperfectly 

 dissolved alone, or perfectly by the aid of acetic acid, a "white 

 precipitate with solution of potash, unless concentrated; in 

 which case the characteristic yellow appears. These acetates 

 remain for further examination. 



4th. — Solutions of 17 grains sublimate and IS dry clear 

 crystals of carbonate of soda were mixed cold, and a similar 

 mixture afterwards made, boiling hot. Dull brick-red preci- 

 pitates fell, without effervescence, the liquor retaining a slight 

 similar tinge. Poured off and set to evaporate, brick-red cry- 

 stalline scales continued to form on the surface till reduced to 

 dryness ; and a minute portion redissolved with the muriate 

 of soda, from which 1 did not succeed in completely sepa- 

 rating it. 



5th. — Solutions of 1 7 grains sublimate and of 7| grains cry- 

 stals of oxalic acid, neutralized with 18 grains carbonate of 

 soda, were mixed warm : — no precipitate ensued. The mix- 

 ture was evaporated nearly to dryness, during which a white 

 powder subsided. Distilled water being poured on to dissolve 

 the muriate of soda, the solution did not affect litmus paper. 



6th. — Similar mixtures were made, containing 9| grains 

 crystals of tartaric acid and 9^ grains crystals of citric acid, 

 similarly neutralized. No precipitates took place on mixing; 

 nor did they redden litmus paper more than the solution of 

 sublimate. Evaporating and setting by to crystallize, produced 

 little effect on the citric solution; but the muriate of mercury 

 crystallized out of the tartaric. They were then three times 

 evaporated to dryness on a water-bath, adding two drachms of 

 distilled water, to wash away the muriate of soda, after each 

 desiccation : but the precipitates were not sufficiently insoluble 

 to allow of an effectual sej)aration ; and the li(|ui(l continued to 

 redden litmus paper, particularly the tartaric, where the de- 

 composition was least complete. All the precij)itates of Ex- 

 periments 5 and 6 became orange-coloured in solution of po- 

 tash. I attempted to produce the oxalate, citrate and tartrate, 

 by combining the acids in aton)ic proportions, with the red 

 oxide and the precipitated carbonate ; but after long digestion 

 AT.S. Vol.6. No, 33. &/)/. 1829. Z in 



