28 ANSWERS TO PRACTICAL 



28. The weights of a piece of syenite -rock in air and tn 

 water were 3941.8 grs. and 2607. 5 grs. Find its spec. grav. 



-Ans. 2.954. 



29. A specimen of green sapphire from Siam weighed in 

 02> 21.45 grs., and in water 16.33 S rs - Required its spec, 

 grav. Ans. 4.189. 



30. A specimen of granite weighs in air 534.8 grs., and tn 

 water 334.6 grs. What is the spec. grav. ? Ans. 2.671. 



3 1 . What is the bulk of a ton of iron ? 



1000 oz. = weight of 1 en. ft. of water. 

 7.8 = spec. grav. of iron. 



7800 oz. = weight of a cu. ft. of iron. 

 82,000 oz. (a ton of iron) -H 7,800 (weight of a cu. ft.) = 4 4 / 



A ton of gold? 



1,000 oz. = weight of a cu. ft. of water. 

 19.34 = spec. grav. of gold. 



19,340 oz.* = weight of a cu. ft. of gold. 

 32,000 oz.* -H 19,340 oz. = 1.6, the no. of cu. ft. 



A ton of copper? 



1000 oz. x 8.9 = 8900 oz. 

 32,000 oz. -* 8900 oz. = 3.6 (nearly) the no. of cu. ft. 



32. What is the weight of a cube of gold 4 feet on each 



side ? 



4 3 = 64, the no. of cu. ft. 

 19,340 oz.* (no. of oz. in 1 cu. ft.) x 64 = 77,360 Ibs. 



33. A cistern is 12 ft. long, 6ft. wide, and 10 ft. deep 

 When full of water, what is the pressure on each side ? 



On one side, 12 x 10 x 5 x 1000 oz. = 600,000 oz. = 37,500 Ibs. 

 On one end, 6 x 10 x 5 x 1000 oz. = 300,000 oz. = 18.750 Ibs. 



34. Why does a dead fish always float on its back ? 



It has its swimming bladder located just under the spine; 

 and this is the lightest part of its body, and, of course, comes 

 to the top as soon as the fish dies. 



* In these solutions the student should notice that avoirdupois weight is used 

 in weighing the gol.l. To be exact, 1,000 oz., the weight of a cu. ft. of water, 

 should be reduced to Troy weight, and the Ib. gold taken as 12 oz. Troy, when 

 the ans. would be about 1.36 cu. ft. 



