Current Literature 729 



wooden mallet applied to the "place-crampon" which holds the 

 gutter (crampon). 



On p. 34, the authors give what purports to be the latest tur- 

 pentine specifications issued by the French Government. As a 

 matter of fact, the Government has issued a more recent circular 

 than that of 1909, namely, one approved by the Secretary of 

 Agriculture, May 17, 1912. Essentially they are the same, but 

 it would have been more exact to quote from the latest "Cahier 

 des Charges." As already explained, an important change has 

 been made in the national methods in the Landes which is not 

 alluded to by the authors. 



As a footnote to p. 35, the authors give a "Comparison of 

 Yields of Crude Gtmi per Inch of Width of Face, French and 

 American Methods." This data might have been of especial in- 

 terest if it had been presented in clearer fashion; to the reviewer 

 the tables in the footnotes are far from clear. It is well known 

 that trees of different sizes will yield different amounts of gum 

 per inch of face; therefore, without this measurement known, the 

 value of these tables, even if they had been clearly presented, is 

 more or less minimized. 



The experiments of tapping Western Yellow pine in Arizona 

 within the Coconino Forest are specially interesting, but it would 

 have made the data of greater value if the local climatic and topo- 

 graphic conditions of the stand tapped had been fully described. 

 What was the altitude? What is the length of growing season? 

 Are the conditions average for the Western Yellow pine belt? 

 As a matter of fact, the writer happens to know personally that 

 the experiments were conducted at the Fort Valley Experiment 

 Station, where climatic conditions are unusually rigorous, much 

 more so than obtains in the average Western Yellow pine stand in 

 Arizona. What would have been the result of these experiments 

 (especially as regards yield and length of season) if timber had been 

 tapped at a slightly lower elevation where the climate was not so 

 severe, on a general southerly exposure. An important point, 

 however, which should have been emphasized in analyzing the 

 advisability of tapping a Western Yellow pine stand is the pos- 

 sible danger of wholesale tapping operations on a species which 

 has to make such a fight for existence. This would apply par- 

 ticularly if trees were tapped on the lower, warmer situations, 

 and, of course, must be considered silviculturally before the ad- 



