486 MANIPULATION. 



sions but turned a different way, and so arranged as to have 

 four rows of nine in a row, will contain an equal number of 

 slides with the last. The rows may be separated from each 

 other by a narrow strip of wood placed across the drawers at 

 right angles to the direction in which it draws out, by which 

 means the objects are prevented from sliding one over the 

 other. The following plan of securing the slides in the 

 drawers of small moveable cabinets, recommended in a work 

 entitled Microscopic Objects, is worthy of mention. " The slides 

 containing the objects are laid flat in double or treble rows; 

 the outer ends of the slides are made to fit into a ledge in 

 the front and back of each drawer; the inner ends of the 

 slides, meeting in the middle of the drawer, are kept down by 

 a very thin slip of wood covered with velvet. In this way 

 the slides do not shake when the cabinet is moved from place 

 to place; every object is seen without removal, and thus no 

 time is lost in making a selection." 



Opaque objects mounted on discs should be kept in drawers 

 or boxes lined with cork, and well protected from dust; each 

 disc should have either a number or the name of the object 

 written on it. 



Labelling Slides, §-c. — The methods of cutting and edging 

 glass slides has already been given at pages 263-4. Those 

 who employ plate-glass generally have the edges of their 

 slides either ground or polished; but others, who prefer flatted 

 crown, usually cover them with paper, which gives them a 

 neat appearance. The slides that are protected with paper 

 are generally those having objects on them mounted either In 

 the dry way or in balsam; and when the paper Is thin, like 

 the common blue, It may often be laid on at one operation, a 

 hole having been previously punched out of the centre of the 

 top and bottom piece of the object. Mr. Topping and others 

 employ green or blue coloured papers, on which some kind of 

 pattern Is printed in gold. These should be cut of the size of 

 the sUde, and a hole punched out of the centre of each for the 

 object ; strips of thin paper are then to be pasted around the 

 edges, and the upper and under surfaces afterwards covered 

 with the figured paper. Some persons stick white labels 



