306 



them with his section-cutting machine was no breach of promise on his part. 

 He willingly mentioned this, and regretted that Dr. Hoggan should not have 

 been with them in consequence of a slight misunderstandiug. He was expect- 

 ing to receive some communication from Dr. Hoggan as to the machine, but had 

 received none, and not knowing his address, was unable to write to him on the 

 subject, so as to make the necessary arrangements in time. 



The President said that he had at the last meeting asked Dr. Hoggan to bring 

 his machine ; but he did not know that he would prepare a paper on the subject, 

 and whilst regretting the circumstance of his absence, he hoped that it would be 

 merely a pleasure deferred, and that they would be favoured with it at some 

 future time . 



Mr. Ingpen read a paper *' On a False Light-excluder for Microscopic Objec- 

 tives" (see p. 262 ante), illustrating the subject by drawings on the blackboard, 

 and by the exhibition of the apparatus applied to a microscope. 



The President, in moving a vote of thanks to Mr. Ingpen for his paper, said 

 he felt sure that it was only necessary to see this little piece of apparatus in 

 order to appreciate its value in cutting off extraneous rays. 



A paper, by Mr. Jas. Fullagar, of Canterbury, " On the development of Hydra 

 vulgaris from Ova,' was read, and was illustrated by a number of beautifully 

 executed drawings. Specimens of Hydra vlridis in further illustration of the 

 paper were exhibited in the room by Mr. Curties. 



The President thought it a very interesting circumstance that a creature so 

 low in the animal kingdom should show so perfect a manner of development. 

 At first sight the ovisacs had very much the appearance of the statoblastsof the 

 Polyzoa. The Hydra was so common, and was so often found at their field 

 excursions, that he hoped many of the members of the Club would be able to 

 add to the paper the results of their own observations. 



The thanks of the meeting were unanimously voted to Mr. Fullagar for his 

 paper. 



Mr. Ingpen exhibited and described an Achromatic Bull's Eye Condenser. 

 This instrument was constructed from the objectives of a binocular opera-glass, 

 one of which was reversed in its cell, and the two cells sci'ewedinto the opposite 

 ends of a short piece of tube, so that the flat side of one lens nearly touched the 

 convex side of the other. The lenses were achromatic doublets. A very perfect 

 image of the source of light was obtained, and the purity of the light was stated 

 greatly to excel that of the ordinary bull's eye. Anyone possessing a binocular 

 opera or field glass could construct this condenser at a very small expense, the 

 lenses being still available for their original purpose. 



The thanks of the meeting were voted to Mr. Ingpen. 



Mr. Golding said he had on a recent occasion used a single photographic lens 

 as an achromatic bull's eye, and found it to answer extremely well. 



Mr. Ingpen said that on showing his condenser to Mr. White he had been 

 asked if it would serve as a low power for dissecting. It would not do for that 

 purpose as it was, but if one of the lenses was reversed it would answer capitally 

 for that purpose, giving a large flat field and fine definition. 



On the motion of the President a vote of thanks was passed to those gentle- 

 men who had contributed to the success of the Soiree by exhibiting on that 

 occasion. 



Twenty-three gentlemen having been proposed for membership, the proceed- 

 ings terminated with a Conversazione, at which the following objects were 

 exhibited :— 



