42 . C. U. Shepard's ReiAy to F. A. Genth. 



" Hitchcockiie, Massive, In coatings and botryoidal. Sometimes con- 

 centric like allophane. H.:=2-75.--3. Gr.r=2-909, Color -white, grey- 

 ish, bluish and rarely with a tinge of green. Lustre vitreous to adaman- 

 tine. Transparent to translucent, 



"Heated in a glass tube, it emits much moisture. B-B., phosphoresces 

 brightly, turning of a pale yellow color, while hot. Infusible. Moistened 

 with nitrate of cobalt and ignited, it assumes a very rich blue color. In 

 the state of powder, when moistened with sulj)huric acid and heated, it 

 tinges the flame of the candle green. With borax it readily melts, at- 

 tended by effervescence, into a transparent glass, which on cooling, has a 

 faint tinge of blue. With soda, it quickly^ changes to a deep yellow 

 color, attended by tlie reduction of oxyd of zinc, and by a deposit of its 

 oxyd upon the charcoal, which has a yellow color while it is hot- Soluble 

 without effervescence, in warm nitric or hydrochloric acid. By full igni- 

 tion, in the state of powder, it loses 29*45 p. c. ; and is inferred to be a 

 hydrated phosphate of alumina, with oxyd of zinc. Occurs in thin crusts, 

 like hyalite, upon the joints of qnartzy mica-slate, at the Canton copper- 

 and lead-mine, in Cherokee county, Ga. It is associated with marcasite, 

 pyrites, galena, chalcopyrite, autoraalite and staurotide. N"amed after 

 Dr. Hitchcock, of Amherst College." 



the 



I will now introduce Dr. GeutVs 



statement concermng 



substance lie Las examined ; and thus place before the reader an 

 opportunity of judging, whether he has here occupied himself 

 with mj mineral, or with something else. 



"On iny late visit to the Canton mine," he observes, "I procured a 

 considerable number of specimens of this interesting new mineral, and the 

 following arc the results of my examinations. 



" With a good magnifier only it can be observed that this mineral has 

 a crrystalline structure. It usually occurs in botryoidal concretions or 

 small mamillary incrustations. Color white, yellowish, bluish and reddish 

 white; powder white. Lustre subresinous, subvitreous and dull. Trans- 

 lucent. 



"It has an argillaceous odor Mhen breathed upon. Brittle; fracture 



uneven. H. = 4-5. Sp. gr. (at 20^ Cels.) about 4-014. 



" Before the blowpipe shrinks, but does not fuse ; with cobalt solution, 



gives a fine azure blue mass; with carbonate of soda on charcoal, yields 



metallic lead incrustations. Dissolves both in boiling nitric and chlor- 



hydric acids, more readily in the latter. The following are the results of 

 my analyses : 



** Insoluble, 

 Chhjriae, - 

 Carbonic acid, 

 Phosphoric acid, 

 Oxyd of lead, 

 Alumina, 



Sesquioxyd of iron, 

 Lime, 



Water, 



I. 



Ill 



not determined, 

 not determined. 



18-74 

 not determined. 



24-69 



0*68 

 1-49 



21*65 



II. 



0*48 p. c. 

 004 « 



1-98 

 18-74 

 29 04 

 2564 



0-90 



1-44 

 20-86 



9902 



<i 



M 



II 



« 



a 



ft 



u 



contains oxygen 1'44 



1050 



2 11 



11*91 



0-27 



069 



lO-S^** 



u 

 n 



« 

 It 



m 



<c 



II 



