112 Fourth Supplement to Dana's Mineralogy. 



!N'os. 1 and 2 by Gregory and Walker, 3 and 4 by Connell, 5 by Quadrat, G by 

 Rochleder. 



Phosphatic nodules. — A plio-pliatic nodule in the brown coal beds near Roth, 

 where are found also remains of plants and fish, afforded the following on analysis 

 by Mr. Hassencamp (Leonh. u. Bronn, 1856, 422): Phosphate of lime 45*575, pijos- 

 phate of magnesia 2*042, phosphate of iron 27*708, magnesia 1'339, lime 4200, 

 alumina 625, organic acid 3'334, water 7*5U0, carbonic acid and loss 7'677 == 100. 

 Color externally pitch-black, within honey-ycIIow inclining to pitch-black. G =2-313. 

 H.=25. 



Aragonite [p. 448, and 11, HI]. — Leydolt has examined the structure of aragonite 

 twins by polarized light, and pubhshed a series of plates of great beauty illustra- 

 ting the subject (Sitzungsb. Wien, xix, 10, Jan. 1856). In some compound crystals, 

 consisting mainly of two crystals, a third is detected in spots or lines through the 

 interior ; and the component crystals in other cases are very strangely interpene- 

 trated by one another. He also shows that in the spines of an Echinus and most 

 shells not pearly, the carbonate of lime is calclte; but when the interior is pearly, 

 this part is aragonite and the outer calcite. In Meleagrina the shell is mostly 

 aragonite. 



AsTRAKANiTE? [p. 379]. — To this place we refer, with a query, a crystallized salt 

 obtained from the soil near Mendoza, South America, by N. H. Bishop, and analyzed 

 by Dr. A. A. Hayes (Proc. Boston Soc. N. H, v, 391, 392). It occurs over the dry 

 country from San Luis de la Punta to the foot of the Andes at a depth of from a 

 few^ inches to two feet; and is especially abundant east of the town of San Juan. 

 It is met with in crystals of indistinct form at the junction of two layers of salt. 

 Hardness above that of calcite. Soluble without residue in water, affording a solu- 

 tion which on evaporation at 1 50^^ F. leaves the salt with some of the original physical 

 characters. Heated loses water readily : at a red heat fuses quietly to a transparent 

 anhydrous liquid, and on cooling, there remains an opaque white crystalline solid. 

 Attracts moisture in the climate of Boston. Composition varying; one sample 

 afforded Dr. Hayes : 



S 40-658 Xa 23-758 Sig 9904 CI 0-260 fi 16-420 = 100. 



This corresponds to 2 of sulphate of magnesia and 3 of sulphate of soda (Mg5) 



29-712, Na§ 52-984), with 7^ of water, and affords the general formula (Jig, S"a)5+ 



l^fl ; while astrakanite corresponds to (j'lg, ]?fa)S+2S, and l^fg and [STa are in equal 

 proportions. Other analyses gave Dr. Hayes more nearly this result, as follows: 



NaCl CrenateCa&Fe,§i Sand 



1-21 0'17 = 100 



1-79 0-30 0*06 = 100 



1-16 0-18 0-06 = 100 



Dried at 90^ F. the amount of water was but 1520 per cent, from which Dr. 

 Ilayes infers that the species may contain normally but l3 instead of 2S, 



Beryl [p. 178, and II].— Dr. Heddle confirms (Phil. Mag., [4], xii, 386) the con- 

 clusion that the Davidsonite of Thomson is nothing but beryl. 



BISMUTHAURITE, Shepard (Shep. Mia, 3d edit., S04).— In particles weighing 

 less than a grain; somewhat malleable, like palladium in color. H.=25 — 3. G.= 

 12-44 — 12 9. Structure hacldy or subfibrous. With nitric or hydrochloric acid a 

 slight reaction, but with the two united slowly dissolves excepting traces of a heavy 

 white precipitate. BE. fuses as soon as touched by the flame, giving off white fumes 

 coloring the support bright yellow as long as it is hot, becoming white when cold ; 

 the globule crystalline on cooling. By continuing the heat, globule reduced half in 

 bulk and comes out pure gold. [Locality not mentioned, but given in Amer. Jour, 

 Sci., [2], iv, 281, as the North Carolina gold region. It is also added in that place 

 that there was a suspicion that the grains were " only a product of the miner's pro- 

 cess of separating his gold by "means of amiUgamation, instead of being a true min- 

 eral production." The author described it in the Jour. Sci. in a note on this account : 

 and he appears still to recognize the suspicious character of the species, as be has 

 put it in fine type in this new edition of his Mineralogy. — n.l 



NaS 



MgS 



s 



48-00 



34-20 



16-42 



45-82 



3319 



18-84 



45-74 



33-31 



19-60 



