Mr. A. H. Church on the Spheroidal State of Bodies. 275 



sufficient to destroy the equilibrium, destroys it also when the 

 discs are in motion. From this it follows, which might also be 

 inferred from other grounds, that the distance of the rotating 

 mass from the vertical axis has no effect, or at least a remarkably 

 small one, on the rotation of the apparatus. 



As it appears convenient to distinguish this apparatus by a 

 name, and inasmuch as it may be used for a great number of 

 experiments on rotation, I would propose for it the name of 

 polytropium or polytrope. 



XLI. On the Spheroidal State of Bodies. 

 By Arthur H. Church, Esq. 



To Dr. Tyndall, F.R.S. ^c. 



Royal College of Chemistry, 

 Dear Sir, March 18, 1854. 



THE successful method by which, in your last lecture, the 

 existence of a space between water in the spheroidal state 

 and the containing vessel was proved by the complete interrup- 

 tion that space offered to the passage of a galvanic current, has 

 induced me to devise a few experiments on the subject. 



I have to describe in the present communication, in the fii-st 

 place, some experiments I have just performed for the purpose 

 of obtaining decisive evidence of the isolation of all bodies in 

 the spheroidal state from the surfaces on which they roll ; and 

 in the second place, to offer a few suggestions as to the probable 

 causes of the phsenomena under consideration. 



It was found by Boutigny, that if into a clean, red-hot pla- 

 tinum capsule acids and alkalies be placed, the acid and alkaline 

 hquids will roll about, repelling one another violently. This, 

 though an interesting example of the suspension of chemical 

 affinity, does not prove the existence of a space between the pla- 

 tinum vessel and the spheroids. 



The first experiment I have to mention was this : — I took a 

 copper basin, three inches in diameter and rather more than half 

 an inch deep, polished its concave surface, and covered it with a 

 thin film of silver by the galvanic process. The plated basin 

 was now brought to a very high temperature, and while thus 

 heated, a few drops of a slightly alkaline solution of sulphide of 

 sodium were poured into it. These drops instantly assumed the 

 spheroidal form and rolled about, making, however, no mark or 

 track upon the silver. The source of heat was now witlidrawn : 

 the temperature was soon so far reduced that the liquid exliibited 

 its normal properties, the space between it and the silver no 

 longer existed, and a black stain of sulphide of silver covered the 

 dish. 



