NOTES AND COMMENTS 509 



Stock dipping laws for the eradication of the cattle tick. In some 

 localities the public dipping- vats have, in recent years, been dynamited 

 and destroyed, largely because stock when dipped is counted and the 

 ownership for tax purposes established. 



R. C. B. 



The Work of the United States Forest Products Laboratory 



The U. S. Forest Service Forest Products Laboratory sends out a 

 brief account of the multiform work which it has in hand and some of 

 its findings. We can only recite briefly the direction of work, inter- 

 esting on account of its variety, and important in extending the more 

 thorough use of wood, thereby increasing its stumpage values. 



Strength tests have been made to the number of 137,000. These 

 data were used in two directions, namely, in classifying woods for box 

 manufacture and in formulating definite rules on the variability in 

 the strength of timber and the laws which govern it. 



Similar grading rules, based upon density classification, as worked 

 out for southern yellow pine, have also been tentatively elaborated for 

 Douglas fir. 



A box-testing machine has developed the fact that increasing the 

 number of nails in the ends increased the strength of the boxes 300 

 per cent. 



Some 3,000 nail-pulling tests seem to have develoi>ed the fact that 

 the holding power of nails has a definite relationship to the density of 

 wood, and that there is practically no difference in strength between a 

 solid beam and a beam made of two planks nailed together. 



In regard to kiln-drying, several discoveries have been made, e. g., 

 steaming wood proved successful in removing case hardening. The 

 new, high-velocity-low-superheat method of rapid drying has proved 

 satisfactory for southern yellow pine, in securing drying to 6 per cent 

 moisture in 64 hours, and to shipping weight in 39 hours, with less 

 than 1 per cent loss. Red gum has been found possible to kiln-dry 

 satisfactorily; so, too, shoe lasts may be kiln-dried in 21 days, which 

 hitherto took one and a half years to air-dry. 



Various materials have been tested for preventing absorption and 

 loss of moisture in wood, the most efifective being paraffin ; high tem- 

 perature treatments, and impregnating the wood with sugar were 

 also efifective. 



