410 Miscellaneous Intelligence. 



taneouBly, to the colour of A is added the complementary colour of 

 B, and to the colour of B is added the complementary colour of A. 

 —Bull. Univ. A. xiii. 113. 



5. Alloy for the Construction of Pumps and Cocks. — This alloy 

 consists of 4 parts of tin, 4 of zinc, and 1 of antimony ; these 

 metals, when fused and well mixed together, have been found well 

 suited to make good pumps. Cock metal is usually an alloy of 

 lead, zinc, and antimony, to which more or less tin is added. The 

 alloy described as good for pumps, is fit for cocks, but one to be 

 mentioned is still better ; of the two parts of a cock, namely, the 

 box and the plug, the latter should be rather harder than the former, 

 and therefore contain more antimony. An alloy of 80 parts of tin, 

 with 20 of antimony, is well suited for the plug, and one consisting 

 of 86 parts of tin and 14 of antimony for the boxes of cocks. — In^ 

 dustriel de Bruxelles. — Bull. Univ. F. xiv. 36. 



§ II. Chemical Science. 



1. New Method of preparing Iodic Acid. Serullas. — Berze- 

 lius shewed that the silicated hydrofluoric acid might be easily 

 volatilized without leaving any residue. Serullas, therefore, hoped 

 by its means to separate the potash from the iodate of potassa, and 

 obtain iodic acid pure ; but, in fact, the acid has power to remove 

 only one part of the alkali, and leaves a tri-iodate as hereafter de- 

 scribed*. As, however, soda does not appear to form an acid iodate, 

 hopes were entertained that the alkali there might be separated by 

 the sihcated hydrofluoric acid, and the following process was de- 

 vised. A solution of iodate of soda was heated with excess of the 

 silicated hydrofluoric acid. When sufficiently evaporated and 

 cooled, the insoluble fluate of silica and soda was separated, and 

 the ebullition slightly continued, a little water being added from 

 time to time. Until the excess of silicated hydrofluoric acid was vola- 

 tilized : this requires some time, but the close of the operation is 

 ascertained by the disappearance of the odour of the acid ; during 

 the ebullition no fear of any reaction on the iodic acid need be 

 entertained. When the liquid is of a syrupy consistence and cold, 

 it is to be put on a filter ; the acid will pass through and leave a 

 small quantity of double fluate on the paper. By further concentra- 

 tion at moderate temperature, it may then be obtained solid. 



This easy process yields much iodic acid; 100 parts of the iodate 

 of soda contains 75 parts of the acid ; it is not quite pure, but 

 sufficiently so for most of the experiments in which it is required to 

 be employed: 100 parts of it by heat left little more than Lpa^ of 

 impurity. — Annates de Chimie^ xliii. 127. 



By subjecting this acid to the following operations, M. Serullas 

 detained it in the crystalline form, which it had never before re- 

 ceived. It was dissolved in water, then mixed with hydrofluoric 

 acid, filtered to separate a white precipitate, and left to evaporate 



* Page 415. 



