HOLLOW TRUNKS 23 



where concrete is too rigid and unyielding, 

 such as in dealing with trunks and branches 

 that are apt to be swayed about in stormy 

 weather. The materials are dry sawdust, that 

 of oak, chestnut, and beech being preferable, 

 and solid asphalt, derived from the refining of 

 petroleum, and which is at present in use for 

 filling the interstices of street pavements in 

 various parts of the Metropolis. 



For filling cavities in heavy swaying 

 branches, one part of asphalt to four of clean, 

 dry sawdust will form a mixture that is non- 

 rigid and yields with the motion of the branch 

 in which it is inserted. In dealing with the 

 trunk, which is more rigid and less affected in 

 stormy weather, a larger quantity of sawdust 

 should be used. The filling is made by stirring 

 dry sawdust into boiling asphalt until the 

 desired consistency is reached, and before the 

 composition has cooled it should be inserted 

 in the previously prepared cavity. As in 

 cement filling, the preparation of cavities to 

 be filled with sawdust and asphalt should be 

 carefully attended to, the decayed wood and 

 all soft and rotten material being removed, and 



