250 TRANS. OF THE ACAD. OF SCIENCE. 



102, or even 103° ; while in some places in the country the heat in the 

 shade rose to 106 and 107°. The dryness of the atmosphere on the mem- 

 orable 2d of September was at one time such that the air contained only 

 l'J per cent, of aqueous vapor or relative humidity. A thunderstorm on 

 the afternoon of the 4th terminated this abnormal condition. 



Dr. Wislizenus remarked, that the positive electricity of 

 the atmosphere during the month of August had been less 

 than he had ever before observed, and that though the ba- 

 rometer might fail to give any indication of a storm, the elec- 

 trometer was much more sensitive to atmospheric changes ; 

 and he thought a few stations in different parts of the coun- 

 try would give much better indications of the direction of 

 approaching storms than the barometer. 



Prof. Richard Owen, of Indiana, gave an account of his 

 late visit to the newly discovered deposit of rock-salt, near 

 New Iberia, on the Gulf coast, in the State of Louisiana. 



He stated that, having heard various accounts of the rock-salt in Lou- 

 isiana, he had naturally felt very anxious to examine the deposit person- 

 ally. At New Iberia, La., in November last, he resigned his commission 

 as Colonel of the 60th Indiana Regiment to accept the chair of Natural 

 Science in the Indiana State University. Learning that the distance from 

 New Iberia to the salt works was not great, he delayed his departure for 

 three days for an opportunity to visit them. This was afforded him 

 through the courtesy of Major-General Franklin ; and, although the day 

 proved very rainy, he was enabled to make a satisfactory examination of 

 the entire locality, under the polite guidance of Mr. Henshaw. 



Fifty years before this period, Mr. Marsh, the father-in-lawof Mr. Hen- 

 shaw, had sunk a well on his plantation, " La Petite Ance," distant in a 

 south-west direction from New Iberia about twelve miles, and only two 

 or three miles from the Gulf of Mexico. The water from this well prov- 

 ing a good brine, Mr. Marsh boiled it down and made considerable quan- 

 tities of salt. When, however, the demand for salt became greater, at the 

 breaking out of the war, Mr. Marsh's son requested permission to sink 

 other wells, hoping to obtain a stronger brine. After digging fifteen feet, 

 one of the negroes employed struck a hard substance with his pick-axe, 

 and was desired by the owner to go on and throw out some of the sup- 

 posed rock. On washing off the excavated mass, it proved to be pure, 

 hard rock salt. 



The area found, at which, by probing to the depth of from 15 to 18 ft., 

 rock-salt was struck, indicates that the deposit underlies several square 

 acres, perhaps four to six. The materials passed through, to reach it, are 

 chiefly bluish clay, sand and gravel, with some lumps of micaceous sand- 

 stone. At the above depth, within that area, under every place at which 

 they have bored or dug down, they reached the solid rock-salt. Through 

 this solid stratum they bored twenty-six feet, and still found the salt de- 

 posit. 



In getting it out for sale, it was found necessary to blast in the usual 

 manner for obtaining building rock; and, even after purchasing moderate 

 sized lumps, the consumer has considerable difficulty in reducing them to 

 a size fit for use. This compactness seems also to protect the salt from 

 deliquescence, and even to enable it for a long period to resist solution 

 when immersed in water. He was assured that large lumps, packed in 

 barrels, had been sunk in creeks and ponds for concealment, and taken 

 up, weeks afterwards, scarcely at all diminished in bulk. 



The accumulation of 15 to 18 feet of clay, sand, and gravel on the de- 

 posit had evidently been the result of comparatively recent washings from 

 the adjoining hills; and the deposit has, no doubt, been worked by the 



