890 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



On this test the machine was worked by an unskilled man, who 

 had never dressed a flour run of stones before, and the time occu- 

 pied by him w^as but one-thi"rd of that usually taken b}^ a skillful 

 miller. 



As the pick is guided l)y the machine, and as every blow is 

 struck perfectly square and true, consequently the edge of the 

 picks do not crumble, but hold an edge much longer, cutting tine, 

 straight and parallel lines at any distance apart required, and giv- 

 ing a system to the work, which it is impossible to attain by any 

 other means ; and as the picks for the machine are inexpensive, 

 compared with hand picks, the saving made in them alone will, in 

 a short time, amount to the cost of the machine. 



Attempts have been made to perform this work wath machines 

 driven by power, all of which have proved futile. 



Owing to the unequal hardness of the stone, and the varied 

 nature of the work, judgment must be exercised in the force given 

 to every blow of the pick, and considering this fact, the inventor 

 believes that a machine, where each blow of the pick is under the 

 complete control of the operator, is the only practical principal on 

 which one can be constructed ; and that considering the simplicity, 

 durability, and many advantages derived by the use of this machine, 

 that it merits a general adoption in flour mills throughout the 

 country. 



FOEMATIOX OF ICEBERGS. 



Dr. Wan-en RowcU read the following extract from a review in 

 the iV. Y. Trihune: 



'■ The central point of the expedition was its arrival at the shore 

 of the Polar sea, in latitude 32° 35' or about five hundred miles 

 from the North Pole. This took place on the 18th of May, 1861. 

 The o])jervations of Dr. Hayes at the place confirm the statements 

 of Dr. Kane, and furnish us with more precise and accurate ideas 

 concerning a locality of such profound geographical interest. The 

 Polar sea extends about the North Pole of the earth, with an 

 average diameter of more than tv/o thousand miles. It is almost 

 entirely surrounded by land ; its shores, for the most part, are 

 well deflned ; the north coasts of Greenland and Grinnell Land, 

 which projects farther into it, being alone undetermined. To a 

 certain extent, these shores are at a uniform distance from the 

 Pole, and are everywhere within the region of perpetual frost. 

 The long line of coast, interrupted in three principal places, 



