MICROSCOPIC OBJECTS. 



43 



as it can hold up and no more, and by these precau- 

 tions the configurations appear alike whenever tried ; 

 whereas, if the water be less saturated, the proportions 

 at different times will be subject to more uncertainty ; 

 and if examined before such separation and precipita- 

 tion of the redundant salts, little more will be seen 

 than a confused mass of crystals. 



The solution being thus prepared, a drop of it must 

 be taken up with a quill and placed on a flat slip of 

 glass, about three quarters of an inch in width, and 

 between three and four inches long, being spread on 

 the glass with the quill, in either a round or an oval 

 figure, till it appears about a quarter of an inch in dia- 

 meter, and so shallow as to rise very little above the 

 surface of the glass. When it is so disposed, it must 

 be held quite level over the clear part of a fire, or over 

 the flame of a candle, at a moderate distance, until the 

 saline particles begin to gather and look white, or some 

 other color, at the extremities of the edges ; then, the 

 microscope being adjusted for its reception, it must be 

 placed under the eye, and brought exactly to the focus 

 of the magnifier ; and, after running over the whole 

 drop, the attention must be fixed on that side where 

 any increase or pushing forwards of crystalline matter 

 from the margin towards the center is observed. 



Figure 9 represents the microscopical appearance of 

 the salt of amber. The shootings of this salt are high- 

 ly entertaining, though the process is very slow ; many 

 spicula shoot from the edge towards the middle of the 

 solution, and from the pointed ends of the spicula, 



Fig. 9, 



great variety of diversifi- 

 ed branches may be ob- 

 served, variously divided 

 and subdivided, and form- 

 ing at last a complete 

 winter scene of trees with- 

 out leaves. 



N. 



