i879-] 
Notes . 
39i 
Eucalypts varies from 5 to 27 per cent. One ton of the fresh 
foliage of E. globulus yields about 8^- lbs. of pearlash ; a ton of 
the green wood, about 2% lbs. ; of dry wood, about 4^- lbs. 
In a petition to the Reichstag concerning the use of alleged 
poisonous colours, the Association for Promoting the Interests 
of German Chemical Industry point out that certain dyes, such 
as red corallin and aurantia, denounced as poisons, have subse- 
quently been proved perfectly innocent. They pray that no 
colour may be prohibited till it has been formally pronounced 
dangerous to public health by a commission of specially qualified 
chemists and physiologists after a due scientific examination. 
While engaged in preparing a Supplement to his “ Handbook 
of Chemical Manipulation, Mr. Greville Williams, F.R.S., made 
inquiries with the view of ascertaining what improvements had 
recently been made in the volumetrical determination of acids 
and alkalies. Amongst the persons consulted was Dr. Otto N. 
Witt, who pointed out that the “ orange 3 ” of Porrier formed an 
excellent substitute for litmus. This new coal-tar derivative was 
introduced into commerce about two years ago : its manufacture 
has, however, been almost entirely, if not quite, abandoned in 
favour of “ orange 4” or tropasolin 00 . This “ orange 3 ” had, 
before its introduction into commerce, been studied indepen- 
dently by Dr. Witt and M. Griess ; and M. Lunge, in the 
“ Berichte der Deutschen Chemischen Gesellschaft,” expressly 
mentions it as an indicator. Its chemical name is dimethyl- 
amido-azo-benzol-sulphonate of ammonium. Different speci- 
mens of litmus somewhat vary in their sensitiveness to acids 
and alkalies ; that with which Mr. Williams experimented in 
comparing “ orange 3 ” and litmus ceased to indicate with sul- 
phuric acid when more dilute than 1 to 50,000. The new indi- 
cator, on the other hand, remained sensitive to 1 part of sulphuric 
acid in 100,000 of water. An immense advantage which this 
indicator possesses over litmus is that it is entirely unaffedled by 
carbonic acid ; the solution need not therefore be boiled, and the 
operation consequently takes much less time ; in facft, four ope- 
rations can be made in the same time as one with litmus. Mr. 
Williams also finds that the new indicator can be employed in 
the determination of ammonia instead of litmus, and has many 
advantages over it. 
M. G. Luvini has preserved the eggs of the silkworm in hy- 
drogen, carbonic acid, oxygen, and nitrogen for about three 
months. Those which had been kept in carbonic acid and in 
nitrogen after removal hatched well and gave an almost com- 
plete yield. 
