PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 429 



American InI^itute Polytechnic Assoclvtion, 

 Dec. 8th 18G4. 



Prof. S. IX Tilljiian pK^sidiiig-. Mr. B. Garvoy, Secretary. 



F. W. (Jeisscnhainer, Esq., cxliibited a specimen of silver ore from Tego 

 mine, at llosario, in the State of Sinola, Mexico, about sixty miles in the 

 interior from Mazatlan. The analysis shows over 1,900 dollars to the ton. 

 This mine has been worked over 130 years, and has, during that time, pro- 

 duced over thirty millions of dollars. It is now producing over thirty thou- 

 sand dollars per month, although worked with old and very imperfect machinery. 

 The ore is a mixture of limestone, quartz, ana the chloride of silver, with 

 small portions of antimony and arsenic. 



The Manufacture of Salt. 



The Chairman said, as an appropriate introduction of the subject to be dis- 

 cussed, he Avould direct attention to an immense specimen of rock salt from 

 the island of St. Domingo. It was token from a large salt deposit found in a 

 mountain. The right to mine for salt has been purchased by an American 

 company. They have recently issued a pamphlet containing interesting 

 statements regarding the locality. 



TURKS ISLAND SALT. 



Mr. eTireh Bull desired to make a few remarks in reference to Turks Island. 

 He recently met an old friend who, many years ago, was supercargo of a ves- 

 sel trading to various parts of the West Indies. In one of his voyages he 

 went to Turks Island, and he described to me the manner in which the salt is 

 made. It is the common impression that the salt is made from the sea water, 

 and that advantage was taken of the flow of the tides, &c., for this purpose. 

 But their method of making salt at that time was very different. It was done 

 by exeavatioKs. The land there is very flat, and they dig down and put boards 

 at the sides. When this is completed the water rises in the opening, which, 

 after remaining some time, crystalizes, and the salt is then raked out and car- 

 ried to the shore, where it is piled in immense heaps, some containingsixty and 

 eighty thousand bushels. A large leaf grown on the island is placed over the 

 heai'S, and the salt remains there until exported. 'The manner in which the 

 salt is placed on ship board is peculiar. The natives of the island carry it in 

 small boats to the vessels, as they have no docks there, and so the vessel has 

 to lay out from the shore. The salt was, at that time, sold for eight cents a 

 bushel. 



Mr. Bull then read, from the Neiv Yoi-k Evening Post, the following 

 account of the 



Salt Springs of New York. 



TIIKIR HISTORY AND PRESENT CONDITION. 



Tlie Onondaga Salines belong to a geological formation extending through 

 western New York and probably into Upper Canada. Salt can be obtained 

 from springs here and there in different counties, but in the Onondaga valley 

 it appears to be most abundant. This is apparently due to the formation of 

 the valley. A stratum of rock cropping out at the north of Onondaga lake 

 underlies the valley, making a tight floor for retaining the water. Above is 



