---------------+------------------------------------------------- | Number of Fire-streams Required Simultaneously. Population of +-----------+-----------+-----------+------------- Community. | 1 | 2 | 3 | 4 | Freeman. | Shedd. | Fanning. | Kuichling. ---------------+-----------+-----------+-----------+------------- 1,000 | 2 to 3 | .. | .. | 3 4,000 | .. | .. | 7 | 6 5,000 | 4 to 8 | 5 | .. | 6 10,000 | 6 to 12 | 7 | 10 | 9 20,000 | 8 to 15 | 10 | .. | 12 40,000 | 12 to 18 | 14 | .. | 18 50,000 | .. | .. | 14 | 20 60,000 | 15 to 22 | 17 | .. | 22 100,000 | 20 to 30 | 22 | 18 | 23 150,000 | .. | .. | 25 | 34 180,000 | .. | 30 | .. | 38 200,000 | 30 to 50 | .. | .. | 40 250,000 | .. | .. | .. | 44 300,000 | .. | .. | .. | 48 ---------------+-----------+-----------+-----------+------------- The discharge of each fire-stream will of course vary with its diameter and the pressure at the fire-engine, but as an average it is reasonable to assume that each stream will discharge 250 gallons per minute. The quantity of water required, therefore, to supply the estimated number of streams given in Table III is found by simply multiplying the number of those streams by 250, to ascertain the total number of gallons consumed per minute. If _x_ is the number of thousand inhabitants in any city, and if _y_ represents the required number of streams, then Mr. Kuichling deduces the following formulæ for _y_ by the use of the preceding tables, i.e., these formulæ express the results given in the preceding table as nearly as simple forms of formulæ permit. ___ { _y_ min. = 1.7√_x_ + 0.033_x_,} { } For Freeman’s data: { _x_ } (1) { _y_ max. = --- + 10. } { 5 } ____ ___ For Shedd’s data: _y_ = √5_x_ = 2.24 √_x_. (2) _x_ For Fanning’s data: _y_ = --- + 9. (3) 10 ___ For the author’s data: _y_ = 2.8 √_x_. (4)