Accessory Apparatus 261 



fall to the required extent. In Page's regulator the mercury 

 is not adjustable in this manner, but regulation is brought 

 about by pushing the inner glass tube up or down so that 

 its aperture may approximate the mercury. All the gas- 

 tubes should be of metal, rubber being used only for the 

 connections to the regulator, which should not exceed an 

 inch or so. Kubber tubing as a permanent gas-fitting is 

 dangerous in many ways. To the right of the oven is seen 

 an ordinary retort stand, with glass funnel in its top ring 

 for filtering water into the enamelled ware cup ; this is for 

 use in mounting the ribbons of sections to the slides, the 

 filtered water in the cup being heated by the Bunsen 

 burner below. The platform upon which the cup is resting 

 is merely a sheet of iron about 8 by 5 inches, having an 

 iron rod riveted to one end. The rod fits into an open boss 

 upon the retort stand and forms a most useful hot bench. 

 The amount of heat is regulated by the iron plate at 

 varying elevations above the Bunsen. The pipes and two- 

 way piece which supply gas to the Bunsen and oven will be 

 seen in the illustration. 



We have now described all the utensils necessary to be 

 obtained, fitted up, and understood before giving any atten- 

 tion to the production of sections. A few other items of 

 quite an inexpensive nature will find a more fitting place 

 for their enumeration as we proceed with our work. 



