Garden Surveying, Levelling, and Mensuration 227 



diameter squared x 7854. Therefore the volume of a circular tank with 

 a diameter of 4 ft. and a depth of 3 ft. is found thus: Area of base = 

 4 x 4 x -7854 = 12-5664 sq. ft. Volume = 12-5664 sq. ft. x 3 f t. = 

 37 -6992 cub. ft. Reckoning each cubic foot equals 6 gal. of water, the 

 number of gallons in the tank = 37'6992 x 6'25 = 236*62 gal. The 

 following table gives the number of gallons contained in circular tanks 

 or wells of various dimensions: 



NUMBER OF GALLONS IN CIRCULAR TANKS AND WELLS 



The contents in cubic feet and gallons may be found in the same way 

 with water pots and hot-water pipes. Thus, a yard of 4-in. hot-water 

 pipe contains 4 x 4 x '7854 = 12'5664 sq. in., the volume is 12'5664 X 

 36 = 452-3904 cub. in., and the water contained is something over 13 pt. 

 Every foot run of 4-in. pipe holds '544 gal. of water weighing 5'44 Ib. 



Flower Pots. It is a little more complicated to gauge the cubic 

 contents of these accurately, because they are not cylindrical, square, or 

 rectangular bodies, but truncated cones broader at the top than at the 

 bottom. The volume of any flower pot may be found by the following 

 rule: To the areas of the two ends add the square root of their product, 

 'multiply the sum by the height of the pot, and one-third of the product 

 will be the volume. Taking a 5-in. or 48-sized pot, which is probably the 

 most largely used size in the trade, the dimensions are: Top width 5 in., 

 bottom width 3 in., depth 4| in. To find volume proceed as follows: Area 

 of top 5 x 5 x '7854 = 19*6 sq. in.; area of bottom 3 x 3 x '7854 = 

 7 sq. in. Product of areas = 19'6 x 7 = 137'2. Square root of 137 = 

 117. Add square root to areas of top and bottom, 19'6 + 7 + 117 = 38. 



171 



Multiply by depth, 4 = 38 x 4J = 171. Divide by 3 = -g- = 57 cub. 



in., the required contents of a 5-in. pot equivalent to 1'64 pt. of water. 



In the same way it may be found that the cubic contents of a 6-in. 

 or 33-sized pot is about 108 cub. in. equivalent to 3'11 pt. of water. 



With the help of this rule it is easy to estimate the quantities of soil 

 or compost required for any particular crop. For instance, if 10,000 Zonal 

 Pelargoniums are to be placed in 5-in. pots (48's), this will mean 570,000 

 cub. in. of soil = 329 cub. ft. = 12 cub. yd. = about 12 tons. 



