Tidlia PycnantliemoMes. 343 



filled with strong diluted acid, the motion is at first very rapid and power- 

 ful, but it soon almost entirely ceases. By partially filling the tumblers 

 with weak acid, and occasionally adding a small quantity of fresh acid, a 

 uniform motion, at the rate of seventy five vibrations in a minute, has 

 been kept up for more than an hour : with a large battery. and very 

 weak acid, the motion might bs continued for an indefinite length of 

 time. 



The motion, here described, is entirely distinct from that produced 

 by the electro-magnetic combination of vi^ires and magnets; it results 

 directly from the mechanical action of ordinary magnetism : galvan- 

 ism being only introduced for the purpose of changing the poles. 



My friend. Prof. Green, of Philadelphia, to whom I first exhibited 

 this machine in motion, recommended the substitution of galvanic 

 magnets for the two perpendicular steel ones. If an article of this 

 kind was to be constructed on a large scale, this would undoubtedly 

 be the better plan, as magnets of that kind can be made of any re- 

 quired power, but for a small apparatus, intended merely to exhibit 

 the motion, the plan here described is perhaps the most convenient. 



Art. XVIII. — Description and History of a new Plant, Tkllia Pyc- 

 nhnthemo'ides ; by Melines Conklin Leavenworth, M. D. 

 of Augusta, Ga. (With a drawing.) 



TO THE EDITOK. 



Waterbury, Ct. May 17th, 1831. 



Bear Sir, — I transmit to you a description and drawing of an 

 American plant, which hitherto appears to have evaded the researches 

 of botanists. The generic name which I have bestowed upon it is com- 

 memorative, and in compliment to my friend, William TuUy, M. Do 

 Professor of Botany, Materia Medica, and Therapeutics, in Yale 

 College, I believe, (with a single exception,) the earliest cultivator 

 of scientific botany, under the Linnjean method, in the state of Con- 

 necticut. Yours Sir, very respectfully, etc. 



M. C. Leavenworth. 



DESCRIPTIO UBERIOR. 



Caulis bi vel tripedalis, quadrangularis, subpubescens, supra me= 

 dium ramosus ; rami numerosi, axillares, subfastigiati, incano4o= 

 mentosi. 



