132 STACKED OR CORD MEASURE 



110. The Measurement of Solid Contents of Stacked Cords — 

 Xylometers. The sohd or cubic contents of stacked cords must be 

 actually measured in order to determine the converting factors for 

 wood as influenced by any of the above conditions. The purpose may 

 be to obtain either an average factor for commercial use, or to further 

 test the effect of crook, diameter or length of sticks specialh' selected. 



Two methods of measurement are available, actual calipering or 

 stereometric ^ calculation, and xylometric - measurement. By the first 

 method, the diameter of each bolt is measured in the middle (Ruber's 

 method) taking two measurements at right angles to obtain the average. 

 The length is measured if necessary, but the sticks are usually cut to 

 a standard length. Split billets cannot be measured by this means, 

 and in this case, the round bolt must first be measured before splitting. 

 The measured wood is piled and the contents of the sticks required to 

 make a stacked cord are totaled for as many cords as possible, to obtain 

 average factors. 



Wood after splitting, or very small crooked or irregular pieces such 

 as branches or root wood, is best measured by a xylometer.^ The dis- 

 placement of water when wood is submerged in a tank is exactly equal 

 to the cubic volume of the wood. The only question is the fo m of the 

 tank and method of measuring the cubic volume of water displaced. 



One plan (invented by Karl Heyer, Giessen, 1846) is to have an 

 overflow spout flush with the water level and to catch and measure 

 water which overflows. 



But this is found to take seven times as long as Reisig's method 

 (Darmstadt, 1837) which employes a tank about 5^ feet high and about 

 twice as wide as the diameters of the largest sticks. The cross-section 

 must be uniform at all points. The scale is worked out for cubic feet 

 and decimals, corresponding to the inch scale in height of water in the 

 tank and is either marked on the inside of the tank, or better on a stand 

 pipe of glass outside the tank, with proper connection, and carefully 

 plumbed. This gives instant readings when a piece is submerged. 

 The endwise position favors complete submersion. 



111. Cordwood Log Rules. The Humphrey Caliper Rule, 1882. Cord- 

 wood log rules are in use in Southern New Hampshire and in Massa- 

 chusetts for measuring the cubic contents of white pine logs in terms 

 of stacked cords and stacked cubic feet. These rules are based upon 

 the principle of the circle inscribed in a square (§ 102). It is assumed 

 that a cord, no matter what the diameter, length or character of the 

 timber, contains 100.5 cubic feet of solid wood. The diameter is cali- 

 pered in the middle of the log outside the bark, but the rule could be 



1 Stereometry, the art of measuring solid bodies. Stereos (Gr.) =solid. 

 ^Xylos (Gr.)^ water. 



