PROCEEDINGS OF THE SOCIETY. 591 



opaque, and then it would colour in such a way that any one looking 

 at it would say at once that it was starch. So far as he had carried 

 out the observations, it seemed as if these starch-grains really did 

 develope, and he thought it might be an instance of the commencement 

 of the process of amyloid deposit. 



Dr. Morris, of Sydney, was introduced to the Meeting by the 

 President, and detailed some experiments which he had made in 

 mounting diatoms in phosphorus in such a way as not to be inflam- 

 mable. As he had only just arrived from Sydney, he had not had 

 time to write anything on the subject.* He had seen some of the 

 specimens which had been mounted in England, and was under the 

 impression that the solution was too strong. He proposed, therefore, 

 to reduce it to such a strength that if a piece of white blotting-paper 

 was put into it, it would not blaze up. By such a solution all difficulty 

 as to using the medium was done away with, the only necessary pre- 

 caution being to have a basin of water near at hand to dip the fingers 

 into. 



Mr. Stephenson said that if they used a weak solution they 

 would get a lower refractive index, whereas the principal object 

 in mounting in phosphorus was to get as great a difference as 

 possible between the refractive index of the medium and that of the 

 object, for on this difference alone the increase of visibility 

 depended. 



Mr. Crisp said that if phosphorus was used diluted to a refractive 

 index of 1*7, the visibility of the diatom would be proportionately 

 reduced, and as there was no virtue in phosphorus, except for its high 

 refractive index, it would be better not to use it at all in such a con- 

 dition, but to take some non-inflammable substance which had the 

 lower refractive index. 



Dr. Morris said that, with regard to the value of the process, he 

 might mention that he had tried some Naviculce, and that with an oil- 

 immersion lens the object mounted in phosphorus was resolved in the 

 most perfect manner — far superior to anything that could be seen with 

 balsam. 



Mr. Crisp said that it must be borne in mind that the danger inci- 

 dental to the use of phosphorus was not confined to the process of 

 mounting. A case recently occurred in which an object-glass, 

 brought down too hard, broke the cover-glass, and the observer, 

 having wiped off the exuding phosphorus with his handkerchief, put it 

 into his pocket and set himself on fire. 



Mr. Ingpen exhibited and described some high-power achromatic 

 eye-pieces, by Steinheil, of Munich (Series A F). They were con- 

 structed for astronomical purposes, but he thought they would prove 

 serviceable for use with the Microscope. Those exhibited were of 

 ^, ^, and ^ inch focus, each having a field of 40° (see p. 551). Mr. 

 Ingpen said that, whatever differences of opinion there might be as to 



* See note by Dr. Morris written after the meeting, supra, p. 579. 



