92 



IHE SEA SHORE 



This consists of a magnifying lens, mounted on a support over a 

 surface on which small objects may be examined and dissected, 

 the height of the lens being, of course, adjusted according to its 

 focal distance. Lenses ready mounted on adjustable stands may 

 be purchased for this purpose, but no one ought to experience 

 much difficulty in designing and constructing some simple stand 

 that will give every satisfaction. 



The arrangement just described is, of course, suitable for the 

 dissection of only small objects, and these are placed on a material 



adapted to the nature of the 

 work to be done. Thus it 

 is sometimes convenient to 

 place the object to be ex- 

 amined on a small sheet of 

 cork, in order that it may be 

 secured by means of pins 

 while the dissection proceeds, 

 while at other times it is 

 essential that it be laid on a 

 hard and unyielding surface, 

 such as that of a slip of glass. 

 But whatever be the nature 

 of the substance on which the 

 dissection is made, its colour 

 may be regulated according 

 to that of the object. If, for 

 example, we are dissecting a 

 small white flower on a piece 

 of cork, we should naturally 

 blacken the cork, or cover it 



with a piece of dead black paper ; or, if we are to dissect a small, 

 light-coloured object on a glass surface, we lay the glass on black 

 paper. 



The advantage of dissecting objects under water does not seem 

 to be generally appreciated by beginners, who often allow their 

 specimens to become dry and shrivelled, almost beyond recognition, 

 during the progress of their examination. This mode of dissection 

 is certainly not necessary with all objects, but may be generally 

 recommended for soft and succulent vegetable structures, as well 

 as for almost all animal dissections. 



This being the case, arrangements should certainly be made to 



FIG. 45. THE TRIPLET MAGNIFIEB 



