WOOD FOR PROFESSIONAL AND SCIENTIFIC INSTRUMENTS 



By Hu Maxwell 



rPHE makers of professional and scientific instru- 

 ' ments in the United States use thirty-five million 

 feet of wood a year, and of thirty-four kinds, ranging in 

 in quantity from twenty 

 million feet for the largest 

 down to a few feet only for 

 those in least demand. Na- 

 tive and foreign woods are 

 on the list, but in both 

 number of kinds and in 

 amount the native species 

 greatly exceed t! ose 

 brought from foreign coun- 

 tries. 



Many articles are includ- 

 ed in this industry, but 

 they may be segregated in 

 a few classes. Of all the 

 instruments belonging in 

 the professional or scien- 

 tific class, the most impor- 

 tant is the lead pencil. It 

 is a simple and small ar- 

 ticle, but it is clearly in the 

 professional class. Two 

 materials, sometimes three, 

 form its constituent parts, 

 namely, wood, graphite and 

 sometimes rubber. In bulk 

 it is chiefly wood, but the 

 substance to which it owes 

 its name is graphite, a min- 

 eral which forms the writ- 

 ing or marking portion of 

 the pencil. The rubber 

 constitutes the eraser, if 



SOURCE OF THE RAW MATERIAL 



The makers of professional and scientific instruments bring 

 woods together from the remote corners of the world, but the 

 accompanying picture represents a typical scene in a northern 

 forest in winter where some of the choicest woods are obtained. 



the pencil has one. Traced to the final source, all three 

 of these substances are wood, though that claim may 

 appear far-fetched. The rubber comes from the rubber 



tree ; the graphite comes 

 from a mine, if not artifi- 

 cial graphite, and it is be- 

 lieved to have once been 

 coal, derived from wood. 

 Immense time, enormous 

 pressure, and a certain 

 amount of heat, were per- 

 haps among the agents of 

 change which transformed 

 wood into graphite and 

 prepared it tor the pencil 

 maker. But in the present 

 article it is not the purpose 

 to go farther back than the 

 wooden slat in dealing 

 with the origin or manu- 

 facture of the lead pencil, 

 leaving questions of geol- 

 ogy and chemistry out of 

 consideration because they 

 are not strictly to the point. 

 Most lead pencils are of 

 cedar, and by common con- 

 sent the best wood for this 

 article is the common 

 southern red cedar, known 

 botanically as Juniperus 

 virginiana. The tree is an 

 evergreen and is found 

 growing naturally from 

 New England to Florida, 

 extending in the southern 



PROCESSES IN LEAD PENCIL MAKING 



The pencil slats which will make from three to six pencils each are passed through various machines before the finished article 

 is ready for market. The steps are shown in the accompanying picture. (Photograph by courtesy of the New York State College 

 of Forestry, Syracuse, New York.) 



