78 REPORT— 1872. 



Arsenic in tlae form of small fragments and coarse powder, was placed in a thick 

 barometer-tube of soft glass and of small bore, well sealed at both ends and enclosed 

 in a piece of wi'ought iron gas-tubing-, closed at each end by an iron screw cap ; the 

 space between the two tubes was tilled with sand, well shaken down ; and the 

 whole was heated to redness by a charcoal fire. Another, similar iron tube, 

 placed beside the former, served to contain several little glass tubes with samples 

 of dift'erent metals, whose fusion might afford some indication of the teniperatm'e 

 at which that of the arsenic occm-red. 



Ai'senic thus treated was found on cooling to have fused into a perfectly 

 compact, crystalline mass of steel grey colour and brilliant lustre, of sp. gr. =5 '709 

 at ly° C. _ 



It possessed a considerable degree of cohesive strength as compared with 

 common sublimed arsenic, and even seemed to exhibit faint traces of flattening 

 before crushing under the hammer. It gradually tarnished on exposure to tlie air, 

 and presented all the chemical properties of ordinary crystalline arsenic obtained 

 by sublimation. The temperature required for fusion lies between the melting- 

 points of antimony and silver. 



The glass tube used was found greatly distended by the tension of the vapour ; 

 and the siliceous sand — even when of the piu'est kind (from Fontainebleau) and 

 previouslj^ well washed with hydi'ochloric acid, and then with water^was cemented 

 together (in a way very interesting in connexion with the historj- of metamorphism) 

 into a kind of artifi.cial sandstone. 



Specimens of fused and semifused arsenic, and of the tubes surrounded by a thick 

 crust of compacted sand, were exhibited to the Section. 



On tlie occurrence of Native Sulphuric Acid in Eastern Texas, 

 By Professor J. W. Maliet, University of Viryinia. 



Not far from the Gulf of Mexico, and within twenty-five or thirty miles to the 

 westward of the Neches river, there occur at several localities (in some instances in 

 the woods, in others in tlie midst of open prairie) small drainage wells and shallow 

 pools of water strongly sour to the taste. This sourness is due to the presence of 

 free sulphuric acid, which is accompanied by various salts, especially aluminium and 

 iron sulphates. At most of these points gases .are continually escaping (hydrogen 

 sulphide, marsh-gas, and carbonic anhydride), the bubbles burning readily on the 

 applicalion of a light. 



At the bottom of the water, in some instances (as at one point where, by means 

 of an artificial bank, a pond has been formed some 250 feet in diameter, known 

 locally as the " Sour Lake ") an earthy crust with intermingled free sulphur is 

 observable. 



A thick, tariy variety of petroleum is found oozing from the surrounding soil, 

 occasionally to such .an extent that sods taken up with a spade are set on fire, and 

 used to give light in the open air at night. At a point in Louisiana, some fifty or 

 sixty miles further east (where, however, the acid water does not occur, though 

 combustible gas and petroleum are met with on the surface) a most remark.able 

 bed of native sulphm-, 100 feet in thickness, has been reached at the depth of 

 4.50 feet by boring, and a shaft is being at present sunk for its exploitation. This 

 large mass of native sulphm- is more or less mingled with calcium carbonate, and 

 imderlain by gypsum. 



The circumstances connected with the occurrence together in this region of com- 

 bustible gases, petroleum, sulphur, sulphuric acid and gypsum, are of great interest 

 in relation to the mineral history of native sulphur. 



The sulphuric-acid water, which seems to be probably .altogether of superficial 

 origin, is worthy of notice trom the unusu.al strength occasionally attained. The 

 water varies yeiy much at the different localities and at different times. In one in- 

 stance a specimen examined by Dr. Mallet contained no less than 5 290 grammes 

 free sulphuric acid (H^SOJ to" the litre, or 370 grains to the imperial gfillon— this 

 exceeding any amount hitherto reported from other localities, unless the acid spring 

 of the Paramo de Kuiz in New Granada be an exceptiop, examined by Lewy, who 



