436 



Dr. J. E. Reynolds on a New Group of [Apr. 20, 



be inverted without any risk of loss. This jelly, inclosing the bright 

 copper-gauze, has remained in my possession for eight months without 

 giving the slightest indications of a disposition to change. 



Small zoological specimens, when inclosed in the same way in a jelly of 

 the mercuric ketone compound, were found to keep well when carefully 

 cleansed before they were sealed up in the gelatinous envelope. 



By evaporation, a liquid containing eight per cent, of the ketone com- 

 pound was obtained, but it pectized in a few jhours. A two per cent, 

 hydrate retained its liquidity for several months. Once a jelly formed in 

 any of these liquids, I have not succeeded completely in reconverting it 

 to the liquid state by very cautious treatment with potassium hydrate, even 

 when aided by diffusion. 



The alcosol of the mercuric ketone compound was obtained by the 

 method adopted by Prof. Graham in preparing the corresponding silicic 

 alcoholate, — that is to say, by adding to a one per cent, hydrate an equal 

 volume of alcohol, and exposing the mixture over quicklime until most 

 of the water was removed : the alcosol remained. This liquid could be 

 boiled without pectizing ; but if the ebullition continued for some time, a 

 jelly was suddenly obtained. This insoluble jelly corresponded to that 

 produced on heating the hydrate, or adding to it any of the bodies capa- 

 ble of pectizing it ; in the former case alcohol, and in the latter water, 

 being associated or united with the mercuric ketone compound. 



It has now been shown that the new body is capable of affording a 

 hydrosol and hydrogel, an alcosol and alcogel\ it must therefore be 

 regarded as a very strongly marked member of Prof. Graham's group of 

 these colloids, though chemically differing widely from previously de- 

 scribed compounds of this class. 



When the colloid hydrate was treated with sulphuretted hydrogen, 

 mercuric sulphide was produced. The liquid filtered from the sulphide 

 yielded acetone on distillation. Digestion with dilute hydrochloric acid 

 likewise effected the decomposition of the colloid body, mercuric chloride 

 being produced and acetone liberated. Nitric and sulphuric acids, when 

 dilute, did not decompose the compound with the same facility as hydro- 

 chloric acid. Treatment of the hydrosol with copper, zinc, or iron at or- 

 dinary temperatures, failed to effect the substitution of either metal for the 

 mercury in the compound. Prolonged contact with each of the two last- 

 mentioned metals caused pectization, the metal subsequently becoming 

 encrusted with a white substance. Heat produced the same result more 

 rapidly. 



When the anhydrous compound was cautiously heated, a quantity of 

 acetone distilled over, and, as the temperature rose, empyreumatic pro- 

 ducts and mercury were evolved. When the heat was suddenly applied, 

 much metallic mercury distilled over, and a minute quantity of a liquid, 

 having the odour of mercuric methide, was produced, together with car- 

 bonic anhydride and other gaseous bodies not particularly examined. If 



