4.50 
Dr. Pearson's Observations 
2. The sword, fig. 1. appears to be the hardest, § 2. i. (a), 
and the dagger, fig. 4. the softest steel of the above instru- 
ments, § 2. hi. (a). 
3. These steel instruments appear to have been tempered, 
at least in the parts destined for cutting, and piercing. 
4. The axe, fig. 2. being all steel, affords a proof that the 
ancients were not acquainted with the art of manufacturing 
soft malleable iron ; nor consequently of welding it with steel ; 
and that the only state of iron which they used, and could 
manufacture, was steel. 
5. Although, it is most probable, that these steel instruments 
were made of steel got directly from the ore, they show that 
the ancients could render such steel very malleable in its ig- 
nited state, §2.1. ( b ); 11. (a) (6 ) ; in. ( b ); iv. (&•) ; and free 
from extraneous matters, and particularly from oxygen. 
6 . The different degrees of hardness and brittleness of these 
instruments may reasonably be imputed to the different pro- 
portions of carbon which they contain; and to the different 
degrees of cold applied in tempering them ; although the ex- 
periments, §2. 1 .(d); 11. (d ) ; in. (d)\ iv. (e), were not 
made with such precision as to demonstrate the reality of these 
assigned causes. 
7. It seems probable that the axe was tempered at a low 
temperature, and had been much hammered : hence its great 
specific gravity before hammering, §2. 11. (c), and the little 
increase of its specific gravity by further hammering; and 
hence the great diminution of its specific gravity by quench- 
ing in its state of ignition to whiteness, § 2. 11. (c). 
8. Iron and steel instruments are destroyed, commonly, by 
the oxygen of water, or oxygen of atmospherical air. The de- 
struction of iron instruments is prevented by whatever prevents 
