ii^W' Scientific Notic^'S'-MisceUanihiti.' [MArcS; 



for the opportunity of adding this specimen to the mineralogical 

 cabinet of the Lyceum. This gentleman, as he informed me, 

 obtained it from the south-eastern shores of Lake Huron, near 

 Point aux Barques, in Michigan Territory. That part of Lake 

 Huron was cursorily examined by me, in the year 1820, in the 

 course of the expedition conducted by Gov. Cass, through the 

 upper lakes, &c. We considered it remarkable, even in a 

 region abounding in rolled rocks, for the great number and va- 

 riety of granite, gneiss, hornblende, and trap bowlders, scattered 

 along the shores of the lake. The water here is generally shallow, 

 and dangerous to approach in vessels ; these bowlder stones 

 sometimes extending and presenting themselves above water for 

 a mile or more from land. But we could not satisfy ourselves, 

 by an examination necessarily partial, that either of the primitive 

 species mentioned, existed there in any other condition than as 

 rolled masses, or displacements of rock strata, contiguous, per- 

 haps, but not observed. Dr. Bigsby has informed me, that he 

 observed the gneiss, in situ, on the north-western shores of this 

 lake. The nearest rock in place, and that which in fact consti- 

 tutes the abraded and caverned promontory of Point aux Barques, 

 is gray sandstone. — (Annals of the Lyceum of Natural History 

 of New York.) 



4. Method of browning Iron. By Mr. J. Duntze, of New-Haven. 



Nitric acid -l ounce. 



Sweet spirits of nitre -i ditto. 



Spirits of wine 1 ditto. 



Blue vitriol 2 ditto. 



Tincture of steel 1 ditto. 



These ingredients are to be mixed, the vitriol having been 

 previously dissolved in a sufficient quantity of water to make, 

 with the other ingredients, one quart of mixture. Previously 

 to commencing the operation of browning a gun-barrel, it is 

 necessary that it be well cleaned from all greasiness and other 

 impurities, and that a plug of wood be put into the muzzle, and 

 the vent well stopped. The mixture is then to be applied with 

 a clean sponge, or rag, taking care that every part of the barrel 

 be covered with the mixture, which must then be exposed to the 

 air for twenty-four hours, after which exposure the barrel must 

 be rubbed with a hard brush, to remove the oxide from the 

 surface. 



This operation must be performed a second and a third time 

 (if requisite), by which the barrel will be made of a perfectly 

 brown colour. It must then be carefully brushed and wiped, 

 and immersed in boihng water, in which a quantity of alkahne 

 matter has been put, in order that the action of the acid uport 



