HOR] ( 66 ) 



if the body measured is absolutely cylindrical, but the trunks 

 of trees are seldom quite perfect cylinders, and therefore 

 some allowance must be made for their divergences. 



To ascertain the true contents by measurement at the 

 diameter, the divisor necessary to be used is 183, and the 

 result will be the same as that obtained by the quarter girth 

 measurement with the 113 divisor. 



The various systems of measurement may be compared 

 in Mr. Burt's "Round Timber Measurement Tables," as 

 he publishes complete tables or ready reckoners of measure- 

 ment by Hoppus by the 144 divisor; by H.M. Customs 

 quarter girth system, by the 113 divisor ; and by the diam- 

 eter, vising the 183 divisor. 



In the home timber trade the Hoppus system has always 

 been in universal use, and both buyers and sellers under- 

 stand that the percentage of error in true measurement 

 represents 27 per cent., or about the average waste in the 

 conversion of logs, so that measvirement with the 144 divisor 

 gives approximately the volume of timber that can be con- 

 verted out of any given log. 



Horizontal Band Saw. A machine in which the band wheels are 

 placed so that the saw travels in a horizontal plane when 

 cutting. 



Horizontal Frames. These have visually only one saw, although 

 occasionally two are used each on separate slide. The saws 

 work horizontally, and the log is carried past the saw by 

 means of a log carriage to which it is fixed. A rack under 

 the table actuated by a pinion provides the feed motion. 



Horizontal Roller Feed Saw Benches. Saw benches having hori- 

 zontal rollers driven by power, for feeding the material past 

 the saw. 



Hornbeam (Carpinus betulus). A fine, compact grained, hard 

 wood, strong but not very durable. Found in Em-ope and 

 America. There are four species, the wood of which is 

 used for cogs, handles of tools, mallets and other purposes 

 where toughness and hardness are considerations. " Beam," 

 in this compound word, is a survival of the old Gothic term 

 for a tree ; it is high-class wood for fuel and burning into 

 charcoal. 



Horse Chestnut (/Esculus hippocastanum). Imported into Britain 

 from Asia. A soft wood of very rapid growth. Possesses 

 whiteness and lightness, but lacks strength and (unless 

 placed underground) durability. Used extensively for 

 temporary buildings and for bobbins ; also for wheelbarrows 

 at furnaces and kilns, as the wood is difficult to burn. 



