PLATE I. 



FIG. i. Simple arrangement for warming an object under the microscope. It- consists of a copper 

 plate (c) with a central oritiee wliirli is cemented to a common object-glass. From the edge of the 

 plate a copper roil i./i projects, t In- end of which can In- heated by a spirit lump. p. 6. 



Flu. u. A similar lm. more complicated apparatus. The copper plate 6 is square. The red e 

 i'niiii its under surface (upper as seen in the drawing), anil fits in a groove <*' u t i" the glass. 

 The groove emls in a hole into which the pin <l tits. 



FIG. =. Strieker's warm stage (simple f..rm). It consists of a block of black vulcanite about 3 

 nchcs long by i', wide, and ' 4 inch thick. The central chamber (6) is closed below by a glass plate, 

 and surrounded at the top by a perforated copper dish <x), the orifice of which is of the same size 

 as the chamber. The chamber is cylindrical. The cNtern of the thermometer surrounds the cham- 

 ber, as shown by the doffed line (./). Its capillary tube lies in a 'n.ugh. one side of which is 

 formed by the back of the block and the other by a metal plate screwed on to it, the form of 

 which is shown in the figure. The tul.e (c| leads into the chamber. A second tube leads from it 

 through the projecting metallic brtri shown at the ti p of thetimnv. This arm, which is of one piece 

 with the disk (a), is of such sixe that the rod, tig. i ;. tit son to it. liy means of this rod the chamber 

 is heated ill the way already explained. In experiments with gases the gas enters by , 

 out through the projecting arm. p. 14. 



FIG. 13. A rod g) intended to fit on the projecting arm of fi. 2 by means of a spiral (/). It 

 answers the same purpose as (./) in lig. i. A similar but much lighter rod is used for fig. 12. 



FIG. 16. Object support of black vulcanite, measuring ? inches by i, with central gas chaml>er a. 

 The gas enters and passes out. by the tube I, />'. The block when in use is fixed with putty on to an 

 ordinary object-glass, and the chamber closed at tho top with a cover-glass. 



