with the Prussiate of Potash. 217 



the inside of the tube, opposite the portion whose colour was 

 changed. The deposition of moisture and change of colour pro- 

 ceeded together along the tube (no moisture being deposited at 

 either extremity beyond the amianthus by which the salt was 

 confined), till the whole had assumed the new colour, when the 

 powder was evidently in a moist state. On introducing the chlo- 

 rine, a portion of common air was expelled, after which no gas 

 came over, the chlorine being slowly generated. That it was in 

 contact with the liquid into which the extremity of the appara- 

 tus was plunged, was manifested by the formation of a dark ring 

 at its surface, within the terminating tube. 



There being in this process, then, no loss, all increase of 

 weight will be due to the absorption of chlorine. Out of a mul- 

 titude of experiments with similar results, I select the following : 



52 grs. gained 4'4 grs. = 2'253 to each atom of 26'625 grs. 

 153-2 grs. ... 12-9 2'248 

 277-5 grs. ... 23'5 = 2'254 



Now these come all so near 2-25, =. half an atom of chlorine, 

 as to leave no doubt that such is the true quantity absorbed. 



When the chlorine is passed over the powder very slowly, 

 little apparent moisture is disengaged, the water, though freed 

 from combination, remaining in contact with the salt ; but if it 

 be generated with great rapidity, as by the direct action of mu- 

 riatic acid on peroxide of manganese, the water of crystallization 

 is also rapidly disengaged, and forms on the sides of the tube in 

 very considerable drops ; and if the quantity of powder acted 

 upon be large, there is at the same time a considerable elevation 

 of temperature caused by the condensation of the gas. 



6. If the yellow powder thus saturated with chlorine be 

 spread out in the open air, and dried without artificial heat, it 

 loses in weight a quantity exactly equal to 3 atoms of water. 



VOL. XI. PART I. E e 



