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SUMMARY OF CURRENT RESEARCHES RELATING TO 



is to show how any ordinary Microscope can readily be used as a 

 projection apparatus by the addition of the small lantern and base- 

 board. 



Ross' Arc Lamp "A". — This lamp (fig. 26) is designed expressly 

 for lantern projection work, and is suitable for a current of 5 to 15 

 amperes. It has all motions for centering, &c, and these are very easily 

 controlled, and the light kept very steady. 



Ross' Arc Lamp "B". — This lamp is similar in general design to 

 the lamp " A," and is designed to meet the requirements of those who 

 wish for a lamp which can be used either for projection or for labora- 

 tory purposes. It is very solidly and substantially made, and has 

 all the motions and adjustments necessary to this class of instrument. 



Both this lamp and the lamp " A " were exhibited to the Society on 

 December 19th, 1900. 



Ross' "Radiant" Jet. — At the exhibition of Messrs. Ross' illumi- 

 nating apparatus at the meeting of the Society on December 19th, 1900, 



Fig. 27. 



this jet (see fig. 27) attracted considerable attention by reason of the 

 splendid light produced, together with its perfect silence. It can be 

 regulated to give any desired amount of light according to the amount 

 of gas consumed. It is entirely novel in form, and has very complete 

 motions for centering, &c. 



Koristka's Abbe Camera Lucida. — An improved form of this ac- 

 cessory has been brought out by Sig. Koristka, of Milan (fig. 28). The 

 mirror is fitted with a graduated arc, and there is a slot in the stem 



