[ 11^ ] 



lEIemente of nDicroacop?* 



$»— XTbe JUBtrument. 



By E. C. Bousfield, L.R.C.P., M.R.C.S., etc. 



THERE are probably no fields of science in which so many 

 workers are to be found as photography, microscopy, and 

 astronomy, and these in the order named. The first and 

 last of these are, however, so dependent upon external conditions 

 of weather, light, and so on, that their pursuit is necessarily 

 limited to favourable seasons, and astronomy especially, with the 

 means available to most amateurs, offers only a limited field. 



The microscopist is limited by no such considerations ; given 

 a spare hour, he can utilise it without difficulty. A lamp his 

 sun, his temperature and weather at his own control, he is always 

 provided with what he needs in this direction, whilst, as to objects 

 of study, the range is so vast that with an instrument of but very 

 moderate capacity no one observer can hope to exhaust the 

 objects available for study and recreation, every one of which has 

 beauties and interest of its own. 



In astronomy the objects differ but little in kind, planets, fixed 

 stars, nebulae, groups, clusters, and meteors ; these exhaust the 

 classes of objects, and of these but few can be usefully studied ; 

 and the photographer finds himself in a very similar position. But 

 the microscopist picks up a leaf, examines it, dissects it, observes 

 the relations of its parts to each other, and to the functions which 

 the whole has to fulfil ; or an insect comes in his way, he studies its 

 organs, notes their correspondences with and differences from those 

 of other insects, and the way in which they fit the possessor for its 

 position in the animal kingdom. A patch of blue mould becomes 

 to him a forest of trees laden with fruit, a stagnant pool a veritable 

 storehouse of forms of life, infinite in variety and beauty ; a patch 

 of mud raised by the anchor, or brought up by the lead of some 

 sea-going vessel, yields to him forms of lowly vegetable and 

 animal remains, which, by their exquisite grace and mathematical 

 regularity of form, lead him to wonder whether any blind process 

 of natural selection or survival of the fittest can have brought 

 them to the state in which he sees them, and whether they are 



