124 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



this fluid ; due care, however, should be exercised in weighing the 

 ingredients, also in seeing that the chloral is of Schering's manufac- 

 ture, and in crusts instead of crystals ; the glycerine should also be 

 pure. Place the articles in a thin open-mouthed bottle, which should 

 be partially immersed in cold water contained in an ordinary saucepan. 

 Heat the water to the boiling-point, and continue the boiling until the 

 chloral is dissolved, which will occur in ten or twelve minutes. When 

 cold the mixture is ready for use. It can be readily removed from 

 the objective and slide with cold water, or if in haste, equal parts of 

 methylated alcohol and water will act more promptly." 



We understand that Mr. Bassett has for some time applied his 

 practical knowledge as a chemist to the problem of discovering a 

 suitable fluid for homogeneous immersion. He places the above result 

 of his labours before the Society in the belief that it will be found of 

 good service. 



Bausch and Lomb Optical Company's Slide-holder. — This (see 

 Fig. 4) is a substitute for a mechanical stage. It consists of a 

 German-silver plate of very light weight, moving on a strong glass 

 plate which forms the immovable stage. Only four small i)oints of 

 the metal plate touch the top of this glass plate, while two prolon- 

 gations of the former, bent downward and backward and acting as 

 springs, press against the under side of the glass plate with just 

 sufficient force to keep the slide-holder in position and to prevent 

 it from slipping off when the Microscope is inclined. Two small 



knobs facilitate the 

 handling of the slide- 

 holder. It is claimed 

 that the arrangement 

 exceeds in smoothness 

 and evenness of motion 

 the ordinary form of 

 movable glass stages, 

 and at the same time, 

 while the movable part 

 is of less weight, the 

 glass plate can be of 

 sufficient strength to 

 guard against easy 

 breaking. The glass 

 stage has later been 

 made circular (and 

 thinner), and the slide 

 carrier revolves. 



Beck's Rotating 

 Holder for Rubber 

 Cells. — Fig. 15 (half 

 size) shows this holder (referred to at p. 1041, vol. iii.), which forms an 

 addition to the list of microscopical appliances in which ebonite is used.* 



Fig. 15. 



* See this Joui-nal, iii. (1880) p. 1082. 



