YIELD OF TURPENTINE AND ROSIN. 6 



COLLECTION OF DATA. 



A careful record was kept of the net weight of all the crude gum 

 collected on the experimental areas, with the exception of the first 

 dipping which was made before the experiment could be started. A 

 record was kept also for each area of the weight and grades of rosin 

 produced and the number of gallons of turpentine as measured at the 

 still. The still had a capacity of 10 barrels, but in order to maintain 

 uniform conditions it was often necessary to hold over several barrels 

 of gum until the next dipping before distilling. 



The " scrape" from each plot was all collected at one time, but in 

 distilling it 12 or 13 barrels formed the unit charge. What was left 

 over was weighed as a basis for calculating the amount of turpentine 

 and rosin represented by all the scrape, assuming the proportion of 

 turpentine and rosin and the grade of rosin to be the same as in the 

 case of the charge distilled. The same method of calculation was 

 employed on a few barrels of "dip" remaining over at the end of the 

 season. In this case the proportion of turpentine and rosin was 

 assumed to be the same as that obtained from the last dipping. This 

 dipping contained less turpentine than the average for the season, 

 owing to the presence of considerable scrape cleaned from the faces 

 and aprons. 



At the beginning of the season, before the experiment proper had 

 started, nine, nine, and four barrels of crude gum had been dipped 

 from the standard, narrow, and double plots, respectively. No 

 record was kept except as to the number of barrels, so an estimate 

 was made of the weight of gum and the yield of rosin and turpentine 

 based on the average weights and yields of the gum from the first 

 few charges immediately following. 



On the standard, and especially on the double-chipping areas, the 

 gum from a considerable number of faces was lost during a large 

 part of the season from causes ordinarily avoidable. The camp and 

 still were located in the double-chipping area and near the standard 

 area. Some of the trees were cut to make room for additional build- 

 ings, some were cut for structural timbers, while others had to be 

 abandoned for various reasons. At the end of the season a careful 

 count of these faces was made and the loss estimated according to 

 the height of the face. Two faces that had been chipped for one- 

 half the season were considered as one face lost for the entire season. 

 The number of faces lost in this manner was subtracted from the 

 original count in each plot, and the number thus obtained was taken 

 as the actual number of faces upon which to base the yields. 



A number of faces in each plot were not chipped a portion or all 

 of the season for causes that might be met with in any operation. 

 These included faces in out-of-the-way corners among undergrowth, 

 and missed intentionally or otherwise by the chipper; those along 



