410 WEIGHTS, MEASURES, AND COINS. 



2. A sledge hammer of 6 or 8 pounds weight, to use in 

 driving the drill. 



3. A. sledge hammer of 10 or 12 pounds weight, for break- 

 ing up the blasted rock. 



4. A round iron spoon, at the end of a wire 15 or 18 

 inches long, for removing the pulverized rock from the drill- 

 hole. 



5. A crowbar, a pickaxe, and a hoe, for removing stone 

 and earth before or after. blasting. 



6. Cartridges of blasting powder, to use in wet holes. 

 They should one-third fill the drill-hole, x^fter the charge 

 is put in, the hole should be filled with sand and gravel 

 alone without ramming. If any ramming material is used 

 plaster of Paris is the best, which has been wet and after- 

 wards scraped to a powder. 



7. Patent fuse for slow match, to be inserted in the car 

 tridge, and to lead out of the drill-hole. 



WEIGHTS, MEASURES, AND COINS. 



For the convenience of the student, the following infor- 

 mation is here inserted, of such weights, measures, and 

 coins, of different countries, as are likely to be met with in 

 the course of his ordinary reading on minerals and mining. 



24 grains, Troy, = 1 pennyweight (dwt.) 



20 dwt. " =1 ounce (oz.) 



12 oz. " = 1 pound (lb.) 



16 drams Avoirdupois, = 1 oz. 



16 oz. " =1 pound. 



112 lbs. " =1 hundred (cwt.) 



20 cwt. " =1 ton. 



1 lb. troy = 5760 grs. troy = 13 oz. 2-65143 drams av. 

 1 lb. av. = 7000 grs. troy = 1 lb. 2 oz. 1 dwt. 16 gr. troy. 



To reduce pounds troy, to pounds avoirdupois, multiply by 

 the decimal .822857 ; or, approximately, diminish by 3-17. 



To reduce pounds avoirdupois, to pounds troy multiply by 

 1-215. 



100 lbs. av. is now the usual 1 cwt., and 25 lbs. the quar 

 ter cwt. 



112 pounds, formerly = 1 quintal. 



100 pounds, now usually = 1 quintal. 

 1 French gramme = 15-433159 grs. troy. 



