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middle and hardly perceptible at the sides of the dam, — a cir- 

 cumstance hardly to be looked for, if, as had been supposed, the 

 vibrations were caused by the action of air confined beneath the 

 sheet. 



Mr. Briggs said he had observed similar vibrations at Lewis- 

 ton, confined wholly to the middle of the sheet, where the water 

 passed down an inclined plane with a sloping surface of thirty 

 feet, the air having no opportunity to get beneath it. 



Dr. Burnett described the appearance of Vermiculite under the 

 microscope, after it has been exposed to the action of fire. He 

 showed that the protruded portion was made up of transverse 

 layers, consisting of three series of planes, one above the other, 

 the lowest being based on a granular matter, and the upper two 

 turning upon the joint at their base. The length of these plates 

 diminished from the lowest to the highest, and their direction was 

 towards the convex side of the curve formed by the Vermiculite. 



Dr. Burnett also exhibited an Entozoon five and a half inches 

 long, from a Cricket. It was one of the Gordiacea. 



Mr. Desor spoke of an appearance which he had noticed 

 on the surface of fresh water, for which as yet no very satis- 

 factory reason had been given. The appearances in question 

 are known in Switzerland by the name of ^^fontaines,^'' springs, 

 because they are supposed to indicate the presence of springs at 

 those places. They consist of long bands of smooth water upon 

 a surface otherwise rufiled. They have been thought to indicate 

 a change of wind ; but they are often oblique to it, even when it 

 blows with violence. In Scandinavia, the fishermen attribute the 

 phenomenon to a fatty substance on the surface, which they 

 regard as the eggs of fishes. Mr. Desor had been informed by 

 Admiral Duperrey, that he had observed the same phenomenon 

 at sea among the Coral Islands of the Pacific. During the sum- 

 mer of 1849, he had himself seen it on Lake Superior. The 

 smooth bands of water were observed running in many directions 

 at the same time, when the surface was not much disturbed- 

 There appeared to be more Infusoria in these places than else- 

 where. There would seem to be good reason for supposing the 

 cause to be the presence of an oily matter, perhaps from the 

 decomposition of substances below. As a proof that they are 



