Heating apparatus. 



Nos. 209 to 211. L. PFEIFFER'S Heating Chamber for heating micro- 

 scopical objects during observation. (See L. PFEIFFER, "Protozoan als Krankheits- 

 erreger etc", 2 nd edition, Jena, 1891.) 



The chamber consists of a mahogany box encasing the whole of the micro- 

 scope, with a window in the front to admit the necessary light. On either side 

 is a closely fitting door through which the specimen can be moved with the 

 fingers. The side walls may also be completely folded back, carrying with them 

 the halves of the back wall, which is divided down the middle. 



The whole (chamber and microscope stand) rests upon a thick metal plate 

 on three legs. The metal plate is heated from below by a micro-burner, No. 212, 

 controlled by a thermo-regttlator, No. 215, and should be adjusted so as to burn 

 with smokeless flame. 



By this means the whole stand and the air surrounding it are gradually 

 brought to the same temperature, so that after a reasonable lapse of time the 

 readings of the thermometer placed in the air space indicate the actual tempera- 

 ture of the object on the stage. 



The temperature may be raised to 45 C (u? F) without risk of injury 

 to the Stand or optical equipment. 



We supply this heating chamber in various forms, suitable for Stands with 

 the older form of fine adjustment and for those with BERGER'S micrometer 

 movement. 



In subsequent orders the factory number of the Stand, intend- 

 ed to be used with the heating chamber, should be given. A tJiermo- 

 regulator, No. 215, as well as a thermometer, accompanies each 

 heating chamber, but the micro-burner, JVb. 212, must be ordered 

 specially. 



Nos. 213 and 214. L. PFEIFFER'S Heating Stage. We are prepared to 

 supply this apparatus as constructed by E. LEYBOLD'S successor, of Cologne. 



