MICROSCOPE IN MANUFACTURES 



Mechanical wood pulp which enters so largely 

 into the manufacture of paper is easily recognised 

 by those who have given a fair amount of attention 

 to the microscopical examination of plant life. 

 Wood pulp is always used in conjunction with some 

 binding material such as cotton or flax fibres. Many 

 different kinds of wood are converted into pulp and 

 of course it requires a considerable amount of experi- 

 ence to say exactly what kind of wood has been 

 used in a certain paper. Some of the woods are 

 poplars of various kinds, others spruces and firs. 

 It is easy to distinguish the conifers as spruces and 

 firs are called, for the reason that the trees bear 

 cones. The little fragments of wood, scattered 

 throughout the paper, have minute circular perfora- 

 j tions upon them, resembling miniature quoits, if 

 ; they belong to the conifers ; none of the other woods 

 possess these '' pits " as they are called. 



Very many other plant remains may be found 

 in paper, for instance hop fibres are used sometimes 

 and their presence is usually shown by remnants 

 of the climbing hooks which, during life, studded 

 the climbing stem of the hop. 



Some of the important animal hairs, used in the 

 manufacture of clothing, may now claim our atten- 

 tion. Wool and silk are of course the most im- 

 portant. The best wool is all obtained from the 

 domestic sheep so let us examine one or two of the 

 easily obtained hairs from this animal. As with 

 the vegetable fibres we may examine them in a drop 

 of water but, in this case, we shall find that we 

 ■ 267 



L 



