FrazEr—On Three Bronze Celts from Co. Mayo. 4285 
of phosphoric compounds, similar to the process by which iron is con- 
verted into steel when long heated in charcoal? We are yet unable to 
test the presence of phosphorus under such circumstances in bronze even 
with the assistance of a spectroscope, but when advancing chemical 
science enables us to recognize phosphorus in minute proportions in 
metallic compounds, we will be in a position to determine how far this 
surmise is correct. 
The remarkable patination of one of these celts deserves more than 
a passing observation ; it is seen in a state of perfection that is of ex- 
eeptional rarity in Irish bronzes, and should be preserved in this con- 
dition. Many of these specimens reach our collections seriously 
injured by attempts at cleaning, and even after rude filing, or the 
application of acids, which utterly destroy much of the interest attached 
to them as objects of antiquarian study. It is unusual for bronzes 
in this climate to approximate to such a brilliant lustre as we observe 
in this specimen, and indeed we have not in the Museum of the 
Academy one of equal beauty. 
