378 THE POPULAR SCIENCE MONTHLY. 



thing only was known that heat would drive the moisture, 

 whether natural or acquired, out of the lumber, if it was only ap- 

 plied hot enough and long enough. 



The physiology of wood, or what is now known as timber 

 physics, was poorly understood by any one, much less by the men 

 who were making the experiments ; for in general they were plain 

 business men, with only ordinary business education, and with no 

 pretensions to scientific knowledge. 



Thus little or nothing was known of the chemistry of woods 

 and absolutely nothing of the effect of heat upon the gums, juices, 

 or fibers. But while these men were not up in the sciences, they 

 possessed what perhaps in this instance stood them in as good 

 stead hard common sense and quick perceptions, that permitted 

 them to learn rapidly by experience and by quickness of observa- 

 tion to note the results upon the woods of various conditions in 

 the course of their experiments. 



Thus it was discovered, by a more or less costly experience, 

 that in all the long list of varieties of timber hardly any two 

 could be subjected to precisely similar treatment with the best 

 results to both ; and it was further found that difference in the 

 source whence the same variety came often required a variation 

 in treatment. 



The next and perhaps the most important discovery made, 

 and probably at the expense of the greatest amount of spoiled 

 lumber, was that a temperature too high at the commencement of 

 the drying process produced unsatisfactory results, and often 

 ruined or greatly reduced the value of high-grade and costly 

 material. Before this fact was discovered, so uncertain had been 

 the process in its effects, other than in producing apparently dry 

 lumber, that an actual prejudice arose against submitting upper 

 grades to the artificial process until fairly weather-dried ; it being 

 found that if a portion of the moisture on and near the surface 

 was evaporated by the natural heat of the sun, the effect of plung- 

 ing the lumber at once into a high temperature when put into 

 the kiln was less injurious. 



Investigation and experiment proved further that this was a 

 perfectly natural theory and one by which Nature herself worked 

 constantly. It was fully and satisfactorily shown that lumber 

 sawed and piled in the winter so as to take advantage of the first 

 cool, dry days of spring, not only dried in better condition, with 

 much less danger of sap stain, checking, and warping, but that it 

 actually dried more completely to the very center of the piece, 

 and in a shorter time. ' 



This was found to be especially true of thick lumber, it proving 

 to be a fact that, while the winter-sawed thick stuff would often, 

 in favorable seasons, become remarkably dry to the very center. 



