COMMITTEES ON BEHALF OF THE GOVERNMENT 229 
hands of the assayer, J. R. Eckfeldt. The report of the Director 
of the Mint, James Pollock, contains a statement regarding 
the nature of the experiments which were made with this bar, 
the results obtained, and the conclusions derived therefrom. He 
first remarks that experiments had been made two years pre- 
viously to determine whether aluminum bronzes could be used for 
medals, that they had resulted negatively, and that then the use 
of such alloys for coins had been suggested. He continues: 
“A further series of experiments was therefore undertaken here, at the desire 
of the Secretary of the Treasury and a committee of scientific gentlemen. The 
latter forwarded to the mint a bar for this purpose, which, by assay, was found to 
contain the proportion of nine parts copper to one of aluminum. ‘Their directions 
were closely followed and the principal results may be briefly stated as follows: 
“The aluminum bronze, in the proportion just stated, is very rigid under the 
rolls, requiring many annealings, and liable to crack and break into plates of 
oblique fracture. .... This hardness gives it a great advantage in wear. Coins 
of the cent size were made of this alloy, of legal bronze, and pure copper. The 
three varieties placed in boxes and rapidly shaken for a long time,** treated equally 
in all respects, lost by attrition in the following ratio: Assuming the aluminum 
bronze as the standard of comparison, the legal bronze lost about three times, and 
the copper about six times as much. ‘This property, however, is of no great conse- 
quence in coins of little value. 
“A point of much greater consideration is the avoidance or mitigation of the 
tendency to change color and become foul from the usual causes, viz., the action of 
oily and saline excretions of the hand; the chemical agencies which are met with in 
market-stalls, and the slops of drinking saloons, and the mere exposure to air and 
moisture. If any metal or alloy could be found that would look well, and keep 
clean with the usage to which our small coins are generally subjected, it would be 
deservedly popular. This can scarcely be expected. A silver coin can be deprived 
of its original beauty and become of such a hue as to have its genuineness called 
into question. Pure aluminum, white at first, assumes a bluish tint by atmospheric 
action; and aluminum bronze, although closely resembling gold at first, was 
found, after being held in the sweaty hand for a few hours, to have received an 
ugly tarnish which destroyed the last argument for employing it in currency. 
“ After these experiments were concluded others were started, in the hope of 
finding a binary or ternary alloy which would answer the required conditions, 
especially as to ductility and keeping color for coins of a grade a little above the 
cent and two cent pieces. After some progress had been made, it became evident, 
© This experiment was suggested by Joseph Henry. 
