t On new Compounds of Carbon and Hydrogen, $c. [1825. 



Upon opening the vessel, the surrounding solution crystallizes 

 rapidly, enveloping the first-formed set of crystals with others, 

 which, however, are very readily distinguished from them in 

 consequence of their immediately assuming a white opake 

 appearance. Upon taking out the crystals, those first formed 

 are found to be much harder than the usual crystals of sulphate 

 of soda, and, when broken, it is found that the opacity is not 

 merely superficial, but that it penetrates them to a considerable 

 depth, and even at times throughout. 



These harder and peculiar crystals are readily obtained by 

 closing up a solution of sulphate of soda, saturated at 180, in 

 a Florence flask, boiling the solution in the flask so as to expel 

 the dir before closing it. Upon standing twenty-four hours, 

 fine groups of crystals are formed. When the flask is opened, 

 the solution deposits fresh crystals ; but on breaking the flask, 

 the latter may be scraped off by a knife in consequence of the 

 superior hardness of the first set. 



The hard crystals when separated are found to be efflo- 

 rescent, like those of the usual kind, and they ultimately give 

 off all their water, leaving only dry sulphate of soda. When 

 a given weight was heated in a platina crucible, one half their 

 weight passed off as water, the rest being dry salt ; they 

 consequently contain eight proportionals of water, or 72 sul- 

 phate of soda, and 8x9 = 72 water. The usual crystals of 

 sulphate of soda contain 10 proportionals of water. 



When crystallized sulphate of soda is heated in a flask, a 

 part of it dissolves in the water present, whilst the rest is thrown 

 down in an anhydrous state. The solution at 180 appears to 

 contain one proportional of salt 72, and 18 proportionals of 

 water 162; from which, if correct, it would result, that when 

 the crystals are heated to 180 of the salt take all the water, 

 whilst | separate in the dry state. 



On new Compounds of Carbon and Hydrogen, and on certain 

 other Products obtained during the Decomposition of Oil by 

 Heat*. [Read June \ t 1925.] 



THE object of the paper which I have the honour of submitting 



at this time to the attention of the Royal Society, is to describe 



* Phil. Trans. 1825, p, 440; and Phil. Mag. Ixvi. p. 180. 



