1869.] EDWARDS — MICROSCOPE. 21 



shall address my remarks according to tlic probable requirements 

 of my readers, as : — 



1st. Young beginners. 



2nd. Professional students. 



3rd. Advanced students or Naturalists. 



4th. Professors or wealthy amateurs. 



I recommend the beginner to choose a light, portable but 

 steady instrument with a good open stage and low powers. Let 

 his first object be to prepare and mount objects and let him confine 

 himself to those adapted for his instrument, such as organs 

 of plants and insects, sections of wood and bone, etc. Let his 

 first book be " Half hours with the Microscope,'' and when he 

 has mastered this, let "Carpenter on the Microscope " be his 

 constant work of reference. Now for the instrument to be 

 chosen : — 



The compound body should have two eje-pieces and two object 

 glasses, the range of power should be from 25 to 250 diameters. 

 The body should have two adjustments — coarse by rack work) 

 and fine by lever — the stage as free and open as possible, the 

 hole not less than 1 inch in diameter. The body should hinge 

 upon its centre so as to balance into a favorable position for 

 the sitter, and the mirror be both plane and concave. The bull's 

 eye condenser should be on a separate stand, and a stage forceps 

 and live box are necessary additions. This, in a box with lock 

 and key, is worth from $15 to $20. 



Nothing less than this is worth calling a " Microscope," and 

 with such an instrument as this a large variety of objects may 

 be mounted' and good work done. The round boxed French 

 Microscopes are mere toys, and no perpendicular Microscope will 

 advance the student in the knowledge of the science for reasons 

 which will hereafter appear. Should your local opticians not be 

 able to fulfil all the conditions of the above instrument, I advise 

 you to order a " Society of Arts prize Microscope," from Field 

 & Son or from S. H. Parkes, Birmingham. Either firm will 

 supply for £3 3s. a good useful instrument, giving full value for 

 the money. To the professional student I should recommend 

 something better than the above, both in stand and powers. The 

 student's Microscope, made by Mr. Pillischer, New Bond St., 

 London, price £5, is the best and cheapest I know of this class. 

 It consists of a good steady well finished brass stand, the body 

 tube screwing off so as to pack into a small case. Two eye pieces 



