890 Royal Society :— 
sometimes blended with serpentine, and at others forms distinct 
beds. In its general aspect it resembles closely the saussurite of the 
associated euphotides, and has probably often been confounded with 
that mineral by previous observers. Hence the densities of 3°2 and 
3°3 assigned by different mineralogists to the saussurites of the Alps, 
while Delesse has shown that the true saussurite of the euphotide of 
Mount Genévre, like that of the Vosges, is a felspar. 
The magnesites of this region form great beds; they are crystal- 
line, and consist of carbonate of magnesia with some carbonate of 
iron, and contain as imbedded minerals in some cases grains of quartz, 
in others felspar and tale, and at other times serpentine, but always 
holding chrome and nickel, the latter as a greenish carbonate, in the 
joints of the rock, or in the form of nickeliferous pyrites. 
These magnesian rocks are not confined to the altered portions of 
this formation ; beds of siliceous dolomite holding protocarbonate of 
iron are found, interstratified with pure fossiliferous limestones, near 
Quebec. The reaction between silica and the carbonates of lime, 
magnesia, and iron, which takes place at no very elevated tempera- 
ture, in the presence of water, producing silicates of these bases with 
evolution of carbonic acid, enables us to understand the process 
which has given rise to the pyroxenes, serpentines, and tales of this 
formation, while the argillaceous limestones, which are not wanting, 
contain all the elements of the garnet-rock. 
The general conclusion deduced from these inquiries, and sustained 
by a great number of analyses, which I hope soon to submit to the 
Society, is, that the metamorphism of these Silurian strata has 
resulted from the chemical reaction, in the presence of water, of the 
elements existing in the original sedimentary deposits. 
“On Determinants, better called Eliminants.” By Professor 
Francis Newman, M.A. 
1. This paper aimed at recommending the introduction into ele- 
mentary treatises of the doctrine of Determinants; which, following 
Professor Boole, it called Hliminants. It exemplified the great aid 
to the memory which the notation affords. It undertook to show, 
that if only so much of new notation be used, as is needed in ele- 
mentary applications, the subject becomes full as easy as the second 
part of algebra. The method of proceeding recommended may be 
understood by the following concise statement. 
If x linear eqq. are given, connecting x unknown quantities ; and 
every eq. is represented by A,a+B,2,+C,4,+---+N,2,=P, (where 
ris 1, 2, 3... in the several eqq.), then, solving for any one of the 
unknowns, we of course obtain a result of the form mv=a. Very 
simple considerations then show, that m and a will be integer func- 
tions of the coefficients: namely, it is easy to prove, that 7 this is 
true for one number z, it must needs be true also for the number 
(n+1); and consequently is generally true. Next, the same ana- 
lysis exhibits, that m=0, 1s the result obtained, when P P, P,... P, all 
vanish: moreover, that if the system presented for solution be the 
(n—1) eqq. 
