On the Benzole Series—Determination of Boiling-points. 257 

 been accurately tested, the errors being known un to 200° P 

 Into a sm all retort of symmetrical shape was in oduccd f coil of 

 platinum wire, and about 100 grammes of toluol reneSlv 

 punned with sodium. Before a perfectly truTtwortW 3 

 could be armed at there were several precautions to taken 

 An allowance had to be ascertained and made for irre-ularities 

 introduced by the partial immersion of the thermometer- Item fn 

 the vapour; and it was found that when the spheroids which 

 form upon the surface of the liquid touch the bulb of L t er 



he X of r meiSed iD ? e Vap0m ^ the ? — var la tions m t o 

 height of the mercury, thus interfering with the constancy of the 



pat g trbu,b Re f a H mbei r g theSe th ^- d taking "cae 

 place the bulb of the retort in a chloride of calcium bath T 

 observed he boihng-point of purified toluole, the bulb of the 

 thermometer just touching the surface of the liquid. The tem 



to J 06 the use was rapid. Between 103 3 and 104° eieht-tenths 

 of he toluole distilled over; and on redistillation, the bS 



Po? ma w-t d h co tT a i i a ; 103 ;^ ?* barometrie *—» £& 



ULr -, ? lu ° le P unfied by sodium) prepared from 



toluyhc acid, exactly the same phenomena were oLned 



Waving now given the more important details of my procedure 

 for the preparation, &c. of pure toluole, I may mention that T 

 subjected benzole (from benzoic add) to the la f tieatment 

 the boding point of benzole thus obtained, and that (from coa l 

 tar) punfied by repeated crystallizations, is, however/ identical 



col IJf ¥ " ( ° btamed fl '° m coal -^pbtha and wood-splr) I 

 col e Cte d for experiment that which came over at about 128° 



fe d^nTwithT ^rf 1 ' SU i phunC aCld ^ SoMon °^romic 

 Ul u US,C bai 'y ta and sodium ' the boiling-point was 



LthKlL redUC - fl d -, The , CUm ° le (fr ° m ***** ^andcS 



Zrn oH nf ^"^V 11 1 1C Same Wa ^ as was al *° the cymole 

 (nom oil of cumin and coal-naphtha). y 



Purific7,rT th f (c01 i reCted ) boiling-points of the liquids thus 

 punned at a uniform barometric pressure of ra -760. 



Formula. • Boiling-point. Difference. 

 Ben Z ol e . . C»H« =C«3(C«H«) 808, 



ioluolc . . C"H°=C«4(C 9 H* ]03-7 22 ' 9 



Xylole . . C">H'°=C 6 5(C 2 H 2 l>>6-2 } 22 ' 5 



Cumole . . C 18 H' 2 =C«6(C 2 II 2 l48-4> 22 " 2 



Cymole . . C 20 Hi4=C«7(C 2 H 2 ) 1707} 22 ' 3 



expennlcnt.d'rr" 8 ^ ?"■ 5? f ° Und the ob ^rvations of other 

 wpenmentaiieti compared with my own. 



Phil. May. S. 4. Vol. 9. No. 59. April 1855. S 



