Royal Irish Academy. 595 



crucible, so as to volatilize the ammoniacal salts and burn away the 

 carbon of the tartaric acid, left the yttria slightly coloured by oxide 

 of chrome. From this latter substance it is separated, but not per- 

 fectly, by the action of a dilute acid ; and by the addition of ammo- 

 nia, or caustic potash, to the solution, the yttria is again recovered. 

 That the substance thus obtained is yttria, seems proved by the fol- 

 lowing considerations : — 



It is separated, though not completely, from acids by ammonia 

 largely diluted with sal-ammoniac, and hence cannot be one of the 

 alkaline earths. 



It is insoluble in potash, and is, therefore, not alumina or glucina. 



After ignition it dissolves readily in dilute acids, and is hence not 

 zirconia or thorina. From zirconia it is further distinguished by its 

 saline solutions being precipitated by ferrocyanide of potassium. 



It is not oxide of cerium, for it does not redden in the exterior 

 flame of the blow-pipe, and because its salts are not precipitated by 

 the sulphate of potash. The quantity of the yttria amounts to at 

 least 3 per cent. 



Dr. Apjohn is still engaged in investigating the composition of py- 

 rope ; and expressed his intention of bringing his results on a future oc- 

 casion in a more detailed form under the notice of the Academy, when 

 he hoped also to be able to assign the true formula of the mineral. 



Mr. Clibborn made the following communication on the subject of 

 the Leyden Jar : — 



" In Brande's Manual of Chemistry, vol. i. ,3rd edition, p. 76, I find 

 it stated, that ' if one Leyden jar be insulated, with its internal sur- 

 face connected with the positive conductor, another jar may be 

 charged from its exterior coating ; and if this second jar be insulated, 

 a third may be charged from its exterior coating, and so on for any 

 number of jars, provided always that the exterior coating of the last 

 jar be connected with the ground.' 



" As my electrifying machine was but small, it occurred to me 

 that I might ©economize both time and labour by constructing a bat- 

 tery of jars so arranged that I should be able to take advantage of 

 this principle, and make one jar charge another, instead of my being 

 obliged to charge the whole series ; for, though they are all con- 

 nected together, and charged by the same operation in the common 

 electric battery, yet the time and labour consumed in charging the 

 battery is exactly the same as if each jar were charged separately 

 and then added to the series. A great saving of labour and time 

 would have been effected had the arrangement of jars answered, for 

 it was exactly the same as that described by Brande, so far as the 

 charging part of the apparatus was concerned ; but when the jars 

 were loaded, or rather should have been loaded, they were made to 

 turn through a quadrant, and form a new arrangement, by which all 

 their outside coatings were connected together by a common conduc- 

 tor. A similar arrangement connected all their inside coatings, which 

 made all the conditions necessary to the perfection of the common 

 battery ; and I found it capable of being chai'ged by the electrifying 

 machine in this form, but it could not be charged to any extent in 



