828 C.M. Warren ona Process of Fractional Condensation. 
1, Warren de la Rue and Hugo Miller,’ in their paper entitled 
“Chemical Examination of Burmese Naphtha and Rangoon 
Tar,” after detailing the preliminary treatment by distillation in 
a current of steam, add that ‘A further separation of the va- 
rious products was effected by repeated fractional distillations; 
but no absolutely constant boiling-points could be obtained, not- 
withstanding the great number of distillations and the large 
quantity of material at command. It is true that considerable 
portions of distillates could be collected between certain ranges 
of temperature, tending to indicate a constant boiling-point; 
nevertheless, it soon became evident that distillation alone could 
not effect the separations of the various constituents, and that 
course must be had to other processes.” The other processes 
resorted to were, treatment with sulphuric and nitric acids, 
either separately or mixed; but still with very imperfect results. 
This acid treatment, which was first proposed by De la Rue, an 
subsequently employed by C. Greville Williams,‘ Schorlemmer, 
and others, will be further noticed below. 
” remarks 
duct of 
” and 
Quarterly Journal af the Chemical Society, 1851, 3, 43. 
® Journal of the Chemical Society, xv, 419. solichkeit, das 
7 Annalen der ii “ Unmoghen 
i er e n. eo Mit den 5? 
Annalen der Chemie und Pharmacie, -exiii, 169, says as follows : ie on 
zu 5° aufgesammelten Destillaten wurde die fractionirte Destillation wi 
Neuem vorgenommen, aber nachdem diese Operation sieben Wochen mit € ; 
ielt ich doeh kei rgend 
2 
z 
= 
z 
id 
‘ 
es 
3 
4 
& 
5 
> 
& 
ES 
& 
ar, er é 
riers eorid nore Nach diesen Versuchen halte ich es fiir ase i 
eindl durch fractionirte Destillationen allein in Producte mit cons 
punkt, zu scheiden.” 
