of Iodine and Oxygen. 847 



the volume of oxygen evolved. I have used very small quantities 

 of the substance ; but as my balance is delicate, I do not think 

 there can be any considerable error in the results. I give those 

 which I consider as the most accurate. 



In one experiment, three grains of the substance afforded a 

 quantity of oxygen equal to 517*3 grain measures of water, and 

 lost in weight "68. In a second experiment, two grains afforded 

 348-3 grain measures of oxygen. In a third experiment, one 

 grain yielded 191 grain measures of oxygen. 



Many experiments that I have lately made, have convinced 

 me, that in my first ])aper I rated the number representing 

 the proportion in which iodine combines too low ; indeed at the 

 time, I stated that my results afforded rude approximations, 

 they demonstrated merely that iodine was represented by a very 

 high number. In an experiment recently made with care, fifty 

 grains of the iode of potassium decomposed by nitric acid, af- 

 forded 32 8 grains of nitre. According to this result, the num- 

 ber representing the proportion in which iodine combines is 

 227*3 ; but I do not venture to state this number as exact, as 

 I am not secure of the purity of the hydrate of potassa from 

 which the iode was made. 



The compound of iodine and oxygen is very soluble in water ; 

 it slowly deliquesces in a moist atmosphere, but remains unal- 

 tered when the air is dry ; its solution first reddens, and then 

 destroys vegetable blues, and reduces other vegetable colours to 

 a dull yellow. When its aqueous solution is heated, as the water 

 rises in vapour, it gradually thickens, gains the consistence of a 

 syrup, becomes pasty, and at length by a stronger heat yields 

 the solid substance unaltered ; unless a sufficient heat is applied 

 to decompose a portion of it, when it gains a purplish tint ap- 

 parently from some iodine set free. The pasty substance that 

 it forms is evidently an hydrate, for it yields moisture during its 

 decomposition. 



Its action upon inflammable bodies is such as might be ex- 

 pected from its composition. When it is heated, mixed with 

 charcoal, sulphur, resin, sugar, or the coml)ustible metals in a 

 finely divided state, detonations are produced ; and its solution 

 rapidly corrodes all the metals to which 1 have ex|)osed it, and 

 it acts both upon gold and platiimm, but much more intensely 

 on the first of these metals. 



When a solution of it is poured into solutions of the alkalies 

 or alkaline earths, or when made to act on their carbonates, 

 oxyiodes or triple compounds of oxygen, iodine, and the metal- 

 lic bases, are the results. By its action on solution of ammonia, 

 a substance is produced apparently the same as that which is 



formed 



