56 BULLETIN" 462, IT. S. DEPARTMENT OF AGBICULTUBE. 



allow the installation of a weir for the measurement of water for 

 experimental purposes, which is done in Orlando. 



The Palatka plant could have been constructed without the portable 

 pipe but at considerably higher cost, as the land is more uneven than 

 that in the Orlando grove. This disadvantage might have been over- 

 come, however, by the use of additional underground piping. It 

 would have been necessary also to have placed a two-opening valve 

 at every second tree row, which would have called for an additional 

 expenditure. It will be possible to install these improvements at a 

 later date if desired. The present system will answer the purpose 

 well but requires more labor for its operation. 



The following specifications, prepared by M. B. Williams, irriga- 

 tion engineer, should be insisted upon when terra-cotta pipe is 

 bought from dealers, as it is of the utmost importance to get the best 

 pipe : 



1. All pipe and specials shall be of the best quality standard vitrified salt- 

 glazed terra cotta, sound and well burned, impervious to moisture, free from 

 cracks, flaws, blisters, or other imperfections. All pipe shall be straight in the 

 direction of the axis. Variations from a straight line greater than 2 per cent 

 of the length of the pipe or from a true circle greater than 4 per cent of the 

 diameter of the pipe will not be permitted. 



2. Each pipe shall be of the hub-and-spigot pattern, with deep and wide 

 sockets. Each hub shall be of sufficient diameter to receive to its full depth the 

 spigot end of the next following pipe or special without any chipping of either 

 and leave an annular space of not less than one-half inch all around for a 

 mortar joint. Each hub shall have a depth from its face to the shoulder of the 

 pipe not less than the following : 6-inch pipe, 2| inches ; 8-inch pipe, 2| inches ; 

 10-inch pipe, 2| inches; 12-inch pipe, 3 inches; 15-inch pipe, 3 inches. The inside 

 of the hub and the outside of the spigot of all sizes shall be grooved. All pipe 

 shall be furnished in 3-foot lengths. All specials shall be furnished in 2-foot 

 lengths. 



3. On all T-branches the branch shall stand at right angles to the run, and 

 have a bell or socket end. 



All pipe and specials shall be delivered f. o. b. cars, and shall be subject to 

 inspection there! Pipes or specials having fire cracks of any kind extending 

 through the thickness and having a length greater than the depth of the hub or 

 socket shall be rejected. Air checks appearing only on the outer surface or in 

 the glaze of the pipe will not be objectionable, but the use of a pipe having air 

 cracks extending through the shell caused by too rapid cooling, will not be 

 accepted. No pipe shall be accepted that has a piece broken from the spigot 

 end longer than the hub or socket; nor which has a piece broken from the bell 

 end if the fracture extends into the body of the pipe, or if such fracture can 

 not be placed at the top of the pipe. All pipe shall give a clear-sounding ring 

 when tested with a light stroke with a hammer. 



The following specifications were prepared for laying the pipe : 



All terra-cotta pipe should be laid below frost and covered with not less than 

 15 inches of earth. Trenches should have the following width of bottom for 

 convenient laying and jointing of the pipe : 



Size of pipe inches__ 6 8 10 12 15 



Width of ditch do 20 24 28 30 34 



