yQ WATER IN MURIATIC ACID GAS ? 



potash ; the substances having a strong attraction for water — the ammoniacal 



mur. a gas by g as to pieces of potash — and the muriatic to dry muriate of 



They were in nm e. The apparatus for making the experiment consisted of 



alternate por- a plain retort of about the capacity of twenty-six cubic inch 



in°an exhaust- measures * wUh a stop-cock ; and of a receiver, with a suitable 



-ed vessel. The stop-cock. The latter was filled over mercury with one of the 



wwdrlven g ases > which from the receiver passed into the exhausted 



from the neck retort, by means of the stop-cocks j the other gas was Intro- 



° f j tl !t v ? ssel ' duced the same way into the retort : and thus alternately about 

 and this being J ' J 



cooled, and ninety cubic inches ot each gas were combined. The muriate 

 the body heat- f ammo nia formed, was of its usual appearance. As it. was 

 diffused over the whole surface of the retort, it was necessary 

 to clear the neck by the sublimation of the salt into the bulb, 

 that if any water was present, it might be detected here in the . 

 second part of the operation. 



All the salt being driven into the bulb of the retort, by the 

 heat of a spirit lamp, the neck was cooled and kept cold -by 

 moistened cloths, whilst the buib was heated by a coke-fire, 

 till the muriate began to sublime, and to make its appearance at 

 the curvature of the vessel. The fire was now withdrawn. 

 It had been gradually and equally applied, and it had been con- 

 tinued for a considerable time, 

 a dew, just The result was examined whilst the bottom of the retort was 



perceptible, still very hot, and whilst that part, where a little of the muriate 

 the neck h a d sublimed, exceeded the temperature of boiling water. 



A dew just perceptible was observed lining the cold neck. 

 The quantity of water was so extremely small, that the globular 

 particles composing this dew could scarcely be perceived by the 

 naked eye, unassisted by a magnifying glass. 



This result appeared to me very decisive. The quantity of 

 gases employed was large -, the water, which ninety cubic 

 inches of muriatic acid gas should afford, is,- according to hy- 

 pothesis, equal to no less than-eight grains. How great is the 

 difference between this quantity and a dew barely perceptible ! 

 which may reasonably be referred to a minute quantity of va- 

 pour in the gases, or to a little moisture derived from the 

 mercury, a small quantity of which entered the retort with the 

 gases, 

 -which seemed Dr. Hope wished to ascertain how much water would pro- 

 about oue- duce such a de\v as was observed. For this purpose he heated 



in 



