]<!ote by Professor J. J. Sylvester. 47 



aluminium looks like a binoxide and silicium a quadroxide. 

 I believe that three of the dots were intended for the Al, and 

 three for the Si ; if I am wrong you will be good enough to 

 settle ihh 2)oint'*. 



Lastly, in the London and Edinb, Phil. Mag. for Decem- 

 ber, you have given as the formula for 

 Can 



" Chabasie Na^ I Si^ + 3 Al SP + 10 H." 



k^ J 



Now mark the differences of these formulae: in the twd 

 first we find 6 atoms of water, in the third IS, and the fourth 



10 atoms. Al intended in the third formula means teroxide of 



aluminium, but I imagine it ought to have been Al, a sesqui- 

 oxide, as in the fourth formula*. 



You will greatly diminish the difficulties which you have 

 thus created by favouring me with the following statements: 



The weight of the atom of lime, potash, soda, aluminium, 

 alumina, silicium, silica, and water, the symbol of each, the 

 number of atoms of each contained in chabasie, and the mode 

 in which you consider that the various silicates which chabasie 

 contains are constituted, with their atomic weights and 

 symbols. 



When you have complied with the above request, I will 

 endeavour to see tvhat I ought ; but at present, with data to be 

 collected from four discordant formulae, I see nothing but 

 confusion. I remain. 



My dear Johnston, yours faithfully, 



London, Dec. 12, 18.38. R. Phillips, 



XII. Note by Professor J. J. Sylvester on his former Paper 

 inserted in the London and Edinburgh Philosophical Ma- 

 gazine for December, 1838. 



University College, Lcndon, Dec. 13, 1838. 

 T HAVE to apologize for calling " original" (in the last 

 -* Number of the Magazine) the theorem of numbers which I 

 termed " a pendent to Horner's theorem." This Mr. Ivory 

 has done me the honour to inform me may be found in Gauss's 

 Disquisitiones Arithmeticcc, page 76. As Horner's extension 



* As evincing the extent to which an accident (against which no care of 

 the piintcr can always sufficiently guard) may occur in this mode of sym- 

 bolizing oxygen, I may mention tliat in the ^;nKi/'of this communication, tiic 

 three dots intended for this Al, had retrograded to the previous word. 



