Historical Account. 11 



into the United States from June 30, 1905, to June 30, 1909, as 32,010,820 

 pounds. This being about 80 per cent of the total export, using the 

 data for 1906-1908 * as a basis, we have a total exportation of crude 

 guayule rubber for four years of 40,013,525 pounds, which amount to 

 20,000 long tons in round numbers, representing, on the basis of 7 per 

 cent extraction of rubber with 25 per cent moisture (5.25 per cent dry 

 rubber), shrub, 286,000 tons; and on the basis of 15 per cent extraction 

 of rubber with 25 per cent moisture (11.25 P er cent dry rubber), shrub, 

 132,000 tons. 



The last two sums give us the highly probable extremes between 

 which the tonnage of shrub represented by crude-rubber exports falls. 

 To the amount must be added the amount of shrub exported, for which 

 figures for two and a half years are available, namely, 2745 tons. We 

 have, therefore, the limits of 288,745 tons and 134,745 tons. 



That the larger amount of shrub is nearer the true amount taken 

 appears to be the case, since the extraction of rubber with 25 per cent 

 moisture has only recently reached 15 per cent, and this is probably 

 not attained by manufacturers in general. For a long time it fell below 

 10 per cent, so that an average extraction of 8 to 10 per cent of rubber 

 (25 per cent moisture) is probably near the truth. This would represent, 

 on the 8 per cent basis, 252,745 tons shrub; on the 10 per cent basis, 

 202,745 tons shrub. 



It is therefore probable that in the neighborhood of 225,000 tons 

 of shrub were disposed of up to June 1909. This, according to Endlich, 

 would be somewhat over half the total original available supply. This 

 estimate agrees with that of some interested informed persons who hold 

 that one-half of the original supply is used. But estimates carefully made 

 for business purposes show that there were at this time at least 200,000 

 tons still available. Of this amount, I myself have seen at least 100,000 

 tons in a comparatively restricted area on three estates. 



Allowing for guayule still remaining on fields which have been gone 

 over, and which in certain well-known cases is in considerable amount, 

 it seems not improbable that the total original amount reached 500,000 

 tons. The amount in Texas in the Big Bend country is not known and 

 must therefore be left out of account, but without it it does not seem 

 probable that the total amount of virgin shrub is sufficient to last more 

 than four to six years at the present rate of consumption. 2 It is likely 

 that the smaller concerns will be closed out, so that, with a reasonably 

 restricted output, the supply may be made to last six to eight years, 

 which is the period during which the solution of the cultivation of the 

 plant must be compassed if it is to keep the industry on its feet. 



1 India Rubber World, September 1909. For 1906 to 1908 the total crude 

 rubber exports were 22,693,489 pounds, while our total imports were 17,917,342 

 pounds. 



2 The recent high prices paid for crude rubbers have stimulated the manu- 

 facture of guayule rubber, which has brought as much as $1.25 per pound. The 

 imports into the United States for the year ending June 1910 were, approximately, 

 10,000 long tons. On the basis stated above, this quantity represents something 

 between 66,000 and 145,000 tons of shrub, but, in view of the improved methods, 

 the smaller figure lies nearer the truth. If we assume a 1 2 per cent extraction, we 

 get 83,300 tons of shrub used in the year. 



