190 



SCIOPTICON MANUAL. 



and a high power consequently in use, the source of 

 light should be drawn farther from the condensing lenses.- 

 A very interesting addition to the microscope consists 

 of a diagonal mirror, whereby the image of the objects, 

 instead of being projected directly on an opaque screen, 

 may be thrown down at right angles on a sheet of paper 

 placed on a table, and a drawing very conveniently 

 made. 



HOLMAN'S SIPHON SLIDE (Fig. 53) allows the passage 

 of a continuous current of water for the purpose of 

 keeping it cool in the focus of light. It is designed 



Fig. 53. 



for showing the circulation of the blood in a tadpole's 

 tail, of the sap in plants, &c. Its price, without the 

 bottles, is 85.00. 



A tank filled with a solution of alum is sometimes 

 used to absorb much of the heat of a beam of light 

 before it falls upon a delicate microscopic object. 



