93 
of salt and snow, from which they were removed and struck 
with the hammer in less than 5". 
Up to Series 10, each set of sixteen nails was made up of 
those of the previous set which were left unbroken, added 
to fresh ones to make up the number. 
Series 1. Temperature of eight cold nails 10°. Of eight 
warm 36°. Height of fall of hammer 2 inches. 
Result. No nails broke. 
Series 2. Temperature of eight cold nails 14°. Of eight 
warm ones 36°. Fall of hammer 2|- inches. 
Result. No nails broke. 
Series 3. Temperature of eight cold nails 2°. Of eight 
others 3G°. Fall of hammer 3 inches. 
Result. One cold nail broke. No warm one broke. 
Series 4. Temperature of eight cold nails 2°. Of eight 
others 36°. Fall of hammer 3-1 inches. 
Result. Two cold nails broke. One warm one broke. 
Series 5. Temperature of eight cold nails 2°. Of eight 
others 3G°. Fall of hammer 4 inches. 
Result. One broke of each sort. 
Series G. Temperature of eight cold nails 0°. Of eight 
others 38°. Fall of hammer 4J inches. 
Result. One broke of each sort. 
Series 7. Temperature of eight cold nails 2°. Of eight 
others 36°. Fall of hammer oj? inches. 
Result. No cold nail broke. One warm nail broke. 
Series 8. Temperature of eight cold nails 2°. Of eight 
others 40°. Fall of hammer 6|- inches. 
Result. Two cold nails broke. One warm nail broke. 
Series 9. Temperature of eight cold nails 2°. Of eight 
others 40°. Fall of hammer 7i; inches. 
Result. Three cold nails broke. Three warm nails broke. 
Series 10. Experiment with the ten left in the last. 
Temperature of five cold nails 2°. Of the five others 40° 
Fall of hammer 8^ inches. 
Result. Two cold nails broke. One warm nail broke. 
Series 11. Experiment with the six left from the last 
