[ 100 J 



XIX. On the Phenomena of the Electricity of Steam, observed 

 hi) Mr. Pattinson and Mr. Armstrong. By M. Peltier*. 



ll/I Y experimental and meteorological pursuits-}- having led 

 -'-*■*- me to study the circumstances which impart electricity 

 to vapours, I am enabled to add some facts calculated to af- 

 ford the explanation of the phsenomenon of Cramlington. 



"When a thick piece of platina slightly convexo-concave (am- 

 bouti), is made i-ed-hot, and water poured upon it, a part of 

 the ph^Enomena which take place is known ; therefore I shall 

 only mention them, although the true explanation of these 

 movements has not, in my opinion, been yet given ; I propose 

 to revert to this subject at another time. 



If the bottom upon which the drop of water rests is flat or 

 very little convexo-concave, it takes the figure of an ellipsis, 

 as has been very correctly observed by M. Auguste Laurent 

 [Aimales de Chimie et dc Physique, vol. Ixii. p. 327). This el- 

 lipsis returning upon itself, there is formed from it another 

 which is perpendicular to it : this one being depressed in 

 its turn, the first one re-appears, and so afterwards. After 

 some moments the elongation of the ellipses diminishes ; 

 but then they are multiplied: others are formed from them 

 at ^3 degrees from the first, making four, marching two by 

 two. The temperature diminishing, the sallies grow feeble ; 

 a greater number occur, but they are small, no longer pos- 

 sessing regular and successive movements. These tumultuous 

 movements resolve themselves into a gyratory movement which 

 has its axis vertical, round which is seen a crenelated crown, 

 the vestiges of the ellipsoidal elongations which are disappear- 

 ing. A little later this movement diminishes in velocity, 

 then it stops, and the drop seems to be in a state of I'epose, 

 and vividly reflects the light. The form of the collective 

 movements of these elongations is in part produced by ex- 

 terior resistances themselves depending on the curvature of the 

 crucible, and on the size of the drop projected. 



On examining the drop of water with a lens during its ro- 

 tation, there are seen in the interior several kinds of move- 

 ments. When the rotation stops, there is a moment of 

 suspense in the resultant, which must arise from interior 

 movements; another rotation is then produced, the axis 

 of which is horizontal, and which leaves the superficies 



* Ann. dc Cliim. ct de Phys., Nov. 1840, p. 330, See the preceding 

 articles. 



[t M. Peltier has lately published an interesting meteorological treatise, 

 " Obscrvatium ct liccherc/ws sur la Formation dcs Trombcs; Paris, 1840)" 

 in which lie ascribes to water-spouts an electrical origin.— Ed.] 



