684 [June 18, 



my house in the directions above indicated, the fall amounting to 

 from 60 to 70 feet. The flat in question connects the two rivers 

 Avon and St. Croix, which unite just below Windsor, and is scarcely, 

 if at all, above high-water mark, being protected from inundation by 

 dykes. The view from my house is bounded in the distance on all 

 sides by ranges of thickly wooded hills, whose average height is 

 about 500 feet, and nearest distance about three miles. 



2. The apparatus used for collecting the electricity of the air was 

 Professor Thomson's water- dropping collector, which consists of an 

 insulated can of copper, having a brass pipe leading from it, through 

 which the water can be discharged by turning a tap. The can 

 stands upon a shelf just inside the window, and the pipe projects 

 through a hole 1| inch in diameter in a board which is inserted 

 under the lower sash of the window. The pipe extends nearly 

 horizontally outside the window to the distance of 3 feet 6 inches 

 from the sill ; and the water, when turned on, flows from the end in 

 a stream so fine, that two or three hours are required to discharge a 

 pailful of water. The end of the pipe is about level with the sill of 

 the window. It is assumed that the effect of the stream of water 

 flowing from the pipe is to reduce the pipe and can to the same 

 electrical potential as the air at the place where the water breaks into 

 drops. The time required to reduce the can to the potential of the 

 air is not more than a minute. In my earlier observations I ob- 

 served the electricity of the air as soon as I could after turning on 

 the water ; but in looking over my observation-book, I found the 

 electricity recorded was uniformly weaker at the first observation 

 than at the second, taken about a minute later. In my later ob- 

 servations I always allowed a full minute. 



3. In the commencement of winter the frost interfered with the 

 system of water-dropping. I first tried to obviate the difficulty by 

 leaving the water running ; but a little always remained in the pipe 

 after the can was emptied, and by freezing burst the pipe. I then 

 shortened the pipe by removing some joints of it. This prevented 

 the bursting of the pipe, the remaining portion being of stouter 

 material than that removed ; and I continued to take observations, 



with the pipe thus shortened, from Nov. 1/th to Dec. 2nd; but as 

 the weather grew colder, the water froze in that portion of the pipe 

 which was inside the window ; and after thawing it on two or three 



