226 E. W. Morley — Volumetric Composition of Water. 



gas. In the furnace at f is a tube filled with copper ; this 

 tube of hard glass is joined to the soft glass tubes of the rest 

 of the apparatus by ground joints made tight with syrupy 

 phosphoric acid. As this part of the apparatus Was not ex- 

 hausted, no difficulty was experienced in keeping the joints 

 tight. At g is a tube containing glass beads and sulphuric 

 acid ; this (as well as the two following tubes) lay horizontally, 

 so that the acid should remain well distributed throughout 

 the beads. At A is a tube filled with powdered potassium 

 hydroxide, and at j is a tube filled with glass wool and phos- 

 phorus pentoxide. At h is a vent through mercury ; at m are 

 two glass stop-cocks in succession, which have been lubricated 

 with syrupy phosphoric acid. Their office is at present simply 

 to regulate the flow of gas when the valve at o is opened. 



At o is a valve consisting of glass tubes containing plugs of 

 fusible metal. Two tubes which are perpendicular to the 

 plane of the paper are seen in section ; between them are 

 placed several inverted U-tubes. Each one contains a plug of 

 metal ; when it is desired to admit hydrogen to the part of the 

 apparatus to the right of the valve, one of the plugs is fused ; 

 when it is desired to close the valve, the glass tube is fused 

 together. It may be noted that with a proper composition of 

 the metal, these valves make a joint as tight as could be de- 

 sired, and that there was no failure by the splitting of the 

 glass tube. By having several of these tubes, it was possible 

 to make and again to cut off the connection between the two 

 parts of the apparatus as often as desired. Of course new 

 tubes were put in before each experiment ; in this way, air 

 was admitted to the tube between the valves o and the stop- 

 cock m, but air never was admitted into the part of the appa- 

 ratus to the left of m except by fracture of the apparatus. 

 To remove the air from the tube mo, a tube was provided ' as 

 shown at n ; from which hydrogen was permitted to escape 

 for a long time before each experiment. When n was closed 

 by fusion, one of the valves at b was opened and the connect- 

 ing tube between m and o was exhausted by the pump which 

 had exhausted the apparatus to the right of o. During this 

 exhaustion, the two stop- cocks m had to withstand a difference 

 of pressure equal to that of the atmosphere. This they could 

 not do without permitting some leakage of hydrogen into the 

 vacuum which was then producing to the right of m. This 

 however, gave no difficulty, the exhaustion of the large volumes 

 e and n had already been accomplished under the security of 

 the perfectly tight metal valve, and then these were shut off, 

 so that the leakage during the subsequent exhaustion of m o jp 

 q r, fig. 1, and a c d, fig. 2, was so slight that a vacuum of 

 1/50000 could be obtained in the small volume in question. 



