OF ARTS AND SCIENCES. 195 



Dr. C. T. Jackson exhibited some specimens of native cop- 

 per, and gave a verbal account of some of the evidences of 

 ancient Indian mining at Lake Superior. Dr. A. A. Hayes 

 stated that the occasion of these samples being on the table 

 was a proper one for him to take, m communicating the fact, 



" that, from extended observations, embracing more than five hun- 

 dred specimens pf the Lake Superior native copper, no instance 

 occurred in which the sHghtest indication was presented of this cop- 

 per having been fused in its present condition. I have investigated its 

 internal structure, by a new method of analysis, which permits all 

 alloys and foreign matters to fall on one side, while the pure copper 

 is separated and weighed as such on the other. In this way, and by 

 little modifications, the highly crystallized structure is exposed to view, 

 the less regularly polarized portions being removed. Whether we 

 subject the solid thick masses, or the thinnest plates, to the operation, 

 one constant result is obtained ; — that this copper has taken its pres- 

 ent varied forms of crystallized masses, more or less fattened, lami- 

 nated, or grooved, by the movements among the parts, composing the 

 rocks in which it is found. If we select a mass which has entered a 

 cavity, we find the crystals with their angles sharp and uninjured, 

 while the mass mainly may have been compressed into a plate. Dis- 

 secting this, the crystals are seen to be connected with and form parts 

 of the original system of crystallization. Flattened and grooved 

 specimens often present on their edges arrow-head-shaped forms, de- 

 rived from regular crystals, crushed and laminated." 



Dr. Hayes, having alluded to a new method, a kind of 

 proximate analysis of metals and alloys, further stated, that 

 it is one which admits of almost universal application. Oper- 

 ating on irons of commerce, he has demonstrated that phos- 

 phorus and sulphur, usually found to be present, are not united 

 to the iron, but with more highly electro-positive metals, such 

 as potassium, sodium, and calcium, the latter most commonly. 

 And in all alloys thus far examined, the compound is a metal 

 in a pure homogeneous state, while one, two, or three definite 

 alloys are distributed, often unequally, throughout the mass. 

 In some tough metals, brittle substances like iron ores, quartz, 

 &c., are found, rendering the method of research one of great 

 interest and importance. 



