ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



101 



only on the melting-point of the materia! used. With the above- 

 mentioned stoves 1)00° C. could he reached ; with platinum stoves, 



Fig. 10. 



Pig. 11. 



Fig. 12. 



1500° C. With pattern No. 1 (fig. 8) the objective can be lowered 

 to a working distance of 5 mm., which with Leitz' objectives would 

 furnish a magnification of 25<s diameters. 



Pattern No. 2 (fig. 9) is for higher magnifi- 

 cations, the object-slide being brought up closer 

 to the objective. A dry system will give 2000 ■ 

 diameters. 



Pattern No. 3 (fig. 10) is arranged for the con- 

 venience of the illuminating system, the object- 

 slide being placed on a laterally projecting slab. With this pattern, 

 however, the constancy of the temperature is evidently liable to be 

 affected by air-currents. On the other hand, changes in the object can 

 be more readily noted. 



Fig. 13. 



