1816.] during the Year 1815, 61 
first place examined the accuracy of Stromeyer’s method of analysis, 
by a long set of rigid experiments. He then analysed 11 dif- 
ferent varieties of arragonite from different places. The result of 
his analyses was as follows: 
(1.) Arragonite from Neumarkt, Saalfeld, Minden, Bastenne, 
and.Limburg, contained no sensible quantity of strontian, or, at 
least, the quantity was so small as not to exceed +!;th of a grain in 
100 grains. 
(2.) One variety of Spanish arragonite contained in 100 grains 
about 3ths of a grain of carbonate of strontian; another variety 
contained 11 grain. 
(3.) Two varieties of French arragonite contained 12 grain of 
carbonate of strontian; another variety contained 21 grains, 
(4.) Arragonite from Budheim contained 2+ grains. 
(5.) Bohemian arragonite contained 11 grain. 
Whether the specimens containing no carbonate of strontian 
were really arragonite or not, we have no means of knowing, as 
Bucholz has not given us a description of their characters ; but 
there can be no doubt that minerals have been improperly con- 
sidered as varieties of arragonite, when, in fact, they belonged to 
quite a different species. Thus Professor John found what is called 
compact arragonite from Hanau in the Breisgau, composed as 
follows: (Schweigger’s Journal, vol. xiii. p. 257.) 
Caghonate/of Nimie! oi). 2 bie he, e's Sic STBS 
Carbonate of magnesia..........0+.. 40°38 
Carbonate of iron and manganese..... 0°83 
Insoluble earthy matter .......... see aS 
WU ALGE aAlel JESS 4's wo) o'y's ase dca eohets orate beer SO. 
100°00 
There can be no doubt, both from this analysis, and from the 
characters of the mineral, as given by John, that it was not a 
specimen of arragonite, but of dolomite. 
The result of Stromeyer’s analysis was that the proportion of car- 
bonate of strontian found in arragonite was either 4 per cent. or 2 
per cent. ; but it has been found since in much smaller quantities. 
Indeed few or none of the subsequent experimenters have been able 
to find 4 per cent. of carbonate of strontian in any specimen of ar- 
ragonate subjected to analysis; but this was probably owing to the 
imperfection of their analysis. 
3. Bergmehl, Mountain Meal.—Fabbroni discovered a bed of a 
peculiar kind of earthy matter at Santa Fiora, between Tuscany 
and the Papal dominions, capable of forming bricks so light as to 
swim in water. his mineral has been admitted into systematic 
books of mineralogy under the name of mountain meal. Klaproth 
lately analysed it, and found its constituents as follows :— 
