Mr. C. Wheatstone on Aluminum. 148 



little clusters of dark pigment-cells, disposed so much after the 

 manner of those of the ciliated arms as to lead to the impression that 

 it is one of the same series, or whorl of organs, to use botanical 

 phraseology. A pectinate gill extends beneath the mantle, along 

 the anterior third of the dorsal region, lying, as in most cases, in 

 advance of the heart. The visceral mass of the body, though elon- 

 gated, is but slightly curved upon itself, not exceeding half a turn. 

 The lobules of the liver, distended with large amber-coloured oil- 

 globules, may be distinctly seen through the transparent outer enve- 

 lope and shell. Single spherical otolithes are contained in the 

 acoustic sacs, and the lingual ribbon is lengthy and flexuous, pre- 

 senting a row of uncini on each side, with a series of minute 

 denticulations, pointing backwards on their anterior and posterior 

 borders. The uncini of opposite sides interlock with one another 

 so closely as to conceal the rudimentary segments of the rachis 

 almost completely. The shell is cartilaginous, transparent, planor- 

 bicular, and perfectly symmetrical, presenting four rows of minute 

 conical tuberculations on its convex or dorsal surface. The gyri of 

 the involute nucleus are so curved as to leave a central perforation ; 

 the mouth of the tube encroaches considerably on the last whorl, 

 and the outer hp is deeply notched between the two lateral rows of 

 tubercles. The author has named the species Jasonilla M'Leayiana. 

 The paper is accompanied with illustrative figures. 



Note " On the position of Aluminum in the Voltaic series." By 

 Charles Wheatstone, Esq., F.R.S. 



Having, through the kindness of Dr. Hofmann, been permitted to 

 examine a specimen of aluminum prepared by M. Claire-Deville, I 

 availed myself of the opportunity to ascertain one of the physical 

 properties of this extraordinary metal, which it does not appear 

 has been yet determined, viz. its order in the voltaic series. The 

 following are the results of my experiments. 



Solution of potass acts more energetically and with a greater evo- 

 lution of hydrogen gas upon aluminum than it does on zinc, cadmium 

 or tin. In this liquid aluminum is negative to zinc, and positive to 

 cadmium, tin, lead, iron, copper and platina. Employed as the po- 

 sitive metal, the most steady and energetic current is obtained 

 when it is opposed to copper as the negative metal ; all the other 

 metals negative to it which were tried became rapidly polarized, 

 whether above or below copper in the series. 



In a solution of hydrochloric acid aluminum is negative to zinc 

 and cadmium, and positive to all tiie other metals above named. 

 With this liquid also copper opposed to it as the negative metal gave 

 the strongest and most constant current. 



Nitric and sulphuric acids are known not to act chemically in any 

 sensible manner on aluminum. With the former acid diluted as 

 tiie exciting liquid aluminum is negative to zinc, cadmium, tin, lead 

 andiron. Tiie current with zinc is strong; with the other metals 

 very weak, and it is |)rolmble that their apparent negative condition 

 is the result of polarization. When aluminum is immersed in dilute 

 sulphuric acid, this metal appears negative to zinc, cadmium, tin 



