in the Night and in Winter, 105 



although not exactly in point, observation not being season- 

 ably made. The wheel was a tub wheel ; it was in the winter 

 season subsequent to a thaw which had cleared the stream 

 of ice; the wind for some-time previous had blown very hard 

 from the northwest, which at that place was opposite the 

 course of the stream, (which was small, barely sufficient for 

 a grist mill,) but had now subsided. The mill was started as 

 usual, in the morning; after running an hour or more, it 

 was observed to slacken; the gate was raised, but soon 

 the wheel went slower than before ; more water was let 

 on, but with little effect : examination was then made for 

 the cause, when it was found that the water was become 

 thick with frost, having a large portion formed into crys- 

 tals, in some measure resembling snow and water. It 

 became so thick in a few minutes that it had not sufficient 

 fluidity to turn the wheel at all, and almost ceased to flow 

 in the stream which had in consequence risen considera- 

 bly. This was about 9 o'clock A. M. ; between 10 and 

 11 the stream became clear, the frost having disappeared. 

 It was probably occasioned, in part at least, by the cold 

 wind blowing with so much force against the current, and 

 mixing with the water that the whole stream vi^as reduced 

 to the freezing temperature and congelation pervaded 

 every part equally. 



Probably you will have communications from persons 

 who have made observations more recently and with more 

 attention. Should any thing, however, related above be 

 considered of use, you are at liberty to dispose of this letter 

 as you may think proper, — being always willing, however 

 feebly, to contribute whatever is in my power to the ad= 

 vancement of science.'' 



2. Extract of an anonymous letter to the Editor* 



The author remarks respecting the supposed accele- 

 ration of water-wheels working during the night and in 

 winter : " This fact is well known to most persons, who 

 have been connected with mills, and I remember many 

 years ago, being asked to give an explanation of the cause^ 



* Post marked Beaufort, S. Carolina, October \% 1824. 



Vol. IX.— No. 1, 14 



