874 A. A. Julien on Minerals of the Key of Sombrero. 
and drusy crusts, adhering to guano and also to the sides of 
Cavities in the limestone. A few are also attached to the 7 
group itself, showing the commencement of the pseudomorph- 
ous process. ‘Two analyses of this material follow, of which I 
is the mean of two almost complete analyses of the same speci- 
men, in which the phosphoric acid was determined by means of 
oxyd of mercury. 
L Il. Mean. 
Moisture, - - *. 08 | . 
Water and organic matter, - 2°99 } hea ar Be 
Sulphuric acid, - - - 3 trace. 19 
Carbonie acid, Ne he trace. “48 24 
Phosphoric acid, -- - 47:07} 46°03 | 46°55 
Magnesia, - - - 3°25 3°92:| 3.59 
ime, - :. : - 44°18] 44:24 | 44-21 
Alumina and sesquioxyd of iron, 54 ‘78 | °66 
Fluorine, - - - trace.| trace.| trace. 
Chlorid of sodium, - - undt. 1:08 
98°50 | 99°50 | 99°54 
In grouping together these results we must of course, in the 
first place give to the percentages of sulphuric and carbonic 
acids their equivalents of lime, and to that of magnesia sufficient 
phosphoric acid to form the salt, 3MgO,PO,. ‘There only re- 
main— 
Atomic ratios. 
Lime, - - - - - 43°78 1°56 8 
Phosphoric acid, - -- - 42:28 58: = 
_ If we calculate to the lime its proportion of phosphoric acid 
to form the bone phosphate, 8CaV, PO,, five per cent of phos- 
phorie acid will still remain uncombined, except with the trifling 
quantity ofaiumina and oxyd of iron. From these considerations, 
et age to elucidate the proper method of combining the re- 
: ‘sults, (a question almost always a matter of great doubt and un- 
___-certainty,) the following arrangement seems the most probable: 
| _ Water and organic matter,- - - - - 298 
tie 
Carbonateof lime, - - - - 
Phosphate of lime (8Ca0, SPO,), - — - 
Phosphates of alumina and iron,- —- 
Chlorid of codium,- - - - 
