Dr. H. Harlan on a new Fossil Genus o/YmhWo Sauri. 409 



air : he thence concluded that the air had always an excess of 

 positive electricity. 



In our experiments we could not draw the same conclusion ; 

 for we have sometimes one electricity, sometimes another, ac- 

 cording to the temperature of the metals. However, new re- 

 searches will without doubt throw light on these pheenomena. 



Electric Phenomena which accompany Combustion. 



The preceding experiments have naturally led us to inves- 

 tigate what took place during the combustion of certain bodies. 

 A sheet of common paper i-olled up, is placed on the wooden 

 capsule ; it is set on fire, and then the flame is made to 

 communicate with the common reservoir by the means of a 

 piece of moistened wood, in order that the electricity may 

 flow out more rapidly, and the paper acquires positive elec- 

 tricity. If we operate in a contrary manner, holding the 

 paper in the hand, and making the flame touch a bit of moist- 

 ened wood placed on the capsule, it is found that the flame 

 takes, on the contrary, the negative electricity. It may then 

 be concluded from these two experiments, that when a piece 

 of paper burns, the paper takes the positive electricity, and 

 the flame the negative electricity. If alcohol be poured into 

 a capsule of copper and set on fire, it will be found by the 

 condenser that the capsule acquires the positive electricity. 



Such are the researches which we have made on the elec- 

 tric effects produced by the contact of certain inflamed gases 

 and metals, and by combustion. They are susceptible of many 

 developments ; but we have, notwithstanding, thought proper 

 to take the liberty of communicating to the Academy the first 

 results which we have obtained in this class of phaenomena. 



LXXI. On a new Fossil Genus, of the Order Enalio Sauri 

 [of Conybeare) : and on a new Species of Ichthyosaurus. 

 By R. Harlan, M.D. * 



\ BOUT sixteen years ago there was deposited by Lewis 

 ■*■ "*• and Clark, in the cabinet of the American Philosophical 

 Society, a fossil organic remain of some unknown marine ani- 

 mal. During the expedition of these gentlemen up the river 

 Missouri in the year 1804, this specimen was found in a ca- 

 vern situate a few miles south of the river, near a creek named 

 Soldier's River. The nature of the soil at this locality they 

 do not mention, but there can be little doubt of its being se- 

 condary ; as a few miles down the river, at Council Bluff", there 



* From the Journal of the Acad, of Xat. Srirnrrs of Philadelphia, vol. iii. 

 p. 331, 339. 



Vol. tik No. 320. Dec. 1824. 3 F are 



