38 ARGON. A NEW CONSTITUENT OF THE ATMOSPHERE. 



iliiiiiiiislietl by about -^^ cubic centimetre, due probably to the snbitioii <>f a little 

 cliloiiiie in tlie small quantity of water pre.sent. 



((i) PliospJior us. — A i)iece of combu.stion-tubin<,', dosed at one end, containing 

 at the clo.sed end a small |>iece of phosphoni.';, was sealed to the mercury reservoir 

 containing argon ; connected to the .same re.servoir was a mercuiy gauge, antl a 

 Sprengel's pump. After removing all air from the tubes argon was a<lmitted to a 

 pressure of 600 nun. 'J'lic miiidh' portion of the cond)ustion-tube was then heated 

 to l)right redness, and the phosphoius was distilled slowly from ])ack to front, 

 so that its vapor should come into contact with argon at a red heat, ^^'hen the gas 

 was hot, the level of the gauge altered ; but on cooling, it retui'ucd 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 versa. In each case, on cooling, no change of pi-essure was 

 observed. Hence it may be concluded that phosphi>rus at a red heat is without 

 action on argon. It may l)e remarked parentheticall}' that no gaseous compound 

 of phospliorns is known which docs not possess a volume diffcM'cnt from tlic sum 

 of those of its cou.stituents. Tiuit no solid compound was formed is sutliciently 

 proved by the ab-sence of contraction. The phosplmrus was largely converted 

 into the red modification duiing the e.\periment. 



(e) Sulpliur. — An e.vactly similar e.xperiment was performed willi sulphur, 

 again with negative residts. It may therefore be concluded that sulphur and argon 

 are without action on each other at .1 ml heat. And again, no gaseous comi)ound 

 of suliihur is known in wliicii the volume of the compound is e(pial to the sum of 

 those of its constituents. 



(f) Tellurium. — As this element has a great tendency to unite with heavy 

 metals, it was thought worth while to try its action. In tins, and in the experi- 

 ments to be described, a different form was given to the apparatu.s. The gas 

 was circulated over the reagent employed, a tube containing it being placccl in the 

 circuit. The gas was dried by passage over soda-lime and plnjsphoiic anhydride ; 

 it then passed over the tellurium or other reagent, then through drying tubes, and 

 then back to the gasholder. That combination did not occur was shown by 

 the unchanged volume of gas in the gas-holder: and it was possible, l)y means 

 of the graduateil cylindei" which .'idmittcd water to the gas-holdei', to judge of 

 as small an absoi-jjlion as half a cul)ic centimetre. The tellurium distilled i-eadily 

 in the gas, giving the usual yellow vapor; and it condensed (juite unchanged, 

 as a black sublimate. The volume of the gas, when all was cold, was unalteied. 



(g) Sodium. — A i)iece of sodium weighing about half a gramme was heated 

 in argon. It attacked the glass of the combustion-tube, which it blackened, owing 



I 



