PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 853 



red, depending upon the amount of peroxyd of iron. Some por- 

 tions of it are soft, with a soapy feel, like steatite ; others slaty, 

 and breaking into thin flakes ; others mottled and gray. A ditch 

 from four to six feet wide and about 500 yards in length, extend- 

 ing partly across the valley of Pipestone creek, reveals what has 

 thus far been done in excavating the rocks. There are indications 

 of an unusual amount of labor on the part of the Indians in former 

 3'ears to secure the precious material. Nearly all of our writers 

 on Indian history have invested this place with a number of legends 

 and myths. They have represented the locality as having been 

 known to the Indians from remote antiquity. It is quite probable, 

 however, that the rock has not been known to the Indians from 

 80 to 100 years, and, perhaps, not even as long a period. There 

 are many rude iron tools scattered about, and some of them were 

 taken out of the ditch last summer in a complete state of oxyda- 

 tion. Prof. Hall regards these quartzite rocks as of the same age 

 as the Huroniun series. Mr. Catlin, who first gave a detailed 

 account of this quarry, sent a specimen to Prof. C. T. Jackson, of 

 Boston, for analysis, and the following is the percentage composi- 

 tion of this rock to which the Professor gave the name Catlinite : 

 Silica, 48.2; alumina, 28.2; water, 8.4; magnesia, 6; peroxyd of 

 iron, 5; oxyd of manganese, 0.6; carbonate of lime, 2.6 (probably 

 magnasia), 1 ; total, 100. 



EXTEACTING PeRFUMES. 



The bisulphide of carbon, a very volatile, colorless liquid, of a 

 foetid smell, readily dissolves the essential oils of flowers, to which 

 they owe their agreeable odor. M. Schnaiter's process for obtain- 

 ing perfumes is to fill a large phial Avith the petals, just gathered, 

 of the flowers he wants to operate upon, and having poured upon 

 them a sufficient quantity of bisulphide of carbon (sulphuret of car- 

 bon) to cork the phial, shake it and let it stand. The bisulphide 

 penetrates into the substance of the petals and expels the water 

 they contain, which goes to the bottom. After six days' mascera- 

 tion, the bisulphide of carbon, charged with the essential oil of the 

 flowers, is decanted into another phial containing fresh flowers, 

 and this operation is repeated four times, after which, if the quan- 

 tity of flowers is considerable, the bisulphide will be highly 

 colored. It is now necessary to separate the bisulphide from the 

 perfume. If the quantity be small, it may be left in the open air, 

 by Avhich the volatile bisulphide will soon be evaporated, and tho 



