232 LORD RAYLEIGH AND PROFESSOR W. RAMSAY ON ARGON, 
= CUD centim., due probably to the solution of a little chlorine in the small quantity 
of water presents 

, closed at one end, containing at 
the closed end a small piece of phosphorus, was sealed to the mercury reservoir 
containing argon; connected to the same reservoir was a mercury gauge and a 
SPRENGEL’S pump. Atter removing all air from the tubes, argon was admitted to a 
pressure of 600 millims. The middle portion of the combustion-tube was then heated 
to bright redness, and the phosphorus was distilled slowly from back to front, so that 
its vapour should come into contact with argon at a red heat. When the gas was hot, 
the level of the gauge altered; but, on cooling, it returned to its original level, 
showing that no contraction had taken place. The experiment was repeated several 
times, the phosphorus being distilled through the red-hot tube from open to closed 
end, and vice versé. In each case, on cooling, no change of pressure was remarked. 
Hence it may be concluded that phosphorus at a red-heat is without action on argon. 
It may be remarked parenthetically that no gaseous compound of phosphorus is 
known, which does not possess a volume different from the sum of those of its 
constituents. That no solid compound was formed is sufficiently proved by the 
absence of contraction. The phosphorus was largely converted into the red modifica- 
tion during the experiment. 
(e) Sulphur.—An exactly similar experiment was performed with sulphur, again 
with negative results. It may therefore be concluded that sulphur and argon are 
without action on each other at a red heat. And again, no gaseous compound of 
sulphur is known in which the volume of the compound is equal to the sum of those 
of its constituents. 
(f) Tellwriwm.—aAs this element has a great tendency to unite with heavy metals, 
it was thought worth while to try its action. In this, and in the experiments to be 
described, a different form was given to the apparatus. The gas was circulated over 
the reagent employed, a tube containing it being placed in the circuit. The gas was 
dried by passage over soda-lime and phosphoric anhydride ; it then passed over the 
tellurium or other reagent, then through drying tubes, and then back to the gas- 
holder. That combination did not occur was shown by the unchanged volume of gas 
in the gas-holder ; and it was possible, by means of the graduated cylinder- which 
admitted water to the gas-holder, to judge of as small an absorption as half a cubic 
centimeter. The tellurium distilled readily in the gas, giving the usual yellow 
vapours ; and it condensed, quite unchanged, as a black sublimate. The volume of 
the gas, when all was cold, was unaltered. 
(g) Sodium.—aA piece of sodium, weighing about half a gramme, was heated in argon. 
It attacked the glass of the combustion tube, which it blackened, owing to liberation 
of silicon ; but it distilled over in drops into the cold part of the tube. Again no 
change of volume occurred, nor was the surface of the distilled sodium tarnished ; it 
was brilliant, as it is when sodium is distilled in vacuo. It may probably also be 
