ON ISOMERIC NAPHTHALENE DERIVATIVES. 363 
known, has shown that a single group, in a position contiguous to the acid 
radicle, has little influence on the limit of etherification, and only affects 
the rate of change: but this is not true of betanaphthol, as 1 chloro- 
betanaphthol yields only about 10 per cent. of ether, although betanaph- 
thol gives over 90 per cent. and nitronaphthol cannot be etherified. 
The effect is, in a measure, the reciprocal of that referred to in Sections 
10 and 13 of a ‘ Synopsis for a Discussion on Laws of Substitution, especially 
in Benzenoid Compounds,’ printed later in this volume. The first act 
in the formation of an ether is probably the association of the group 
which becomes etherified with the etherifying agent ; but the attractive 
power of the phenolic oxygen is much affected by changes in the radicle 
with which it is associated, and consequently both the rate and limit of 
etherification are modified by every change in the hydrocarbon radicle. 
Probably the carbonyl oxygen in acids plays a part similar to that here 
pictured as played by the hydroxylic oxygen in naphthol. 
But it is not improbable that the nucleus also plays a part in etheri- 
fication, especially as betanaphthol—in which the nucleus is obviously less 
saturated than is the nucleus in phenol—yields so much larger a proportion 
ot ether than does phenol. Under the most favourable conditions phenol 
affords at best about 25 per cent. of ether when digested with alcohol and 
sulphuric acid. 
The Action of [ight upon Dyed Colowrs.—Report of the Committee, con- 
sisting of Professor T. E. THorPE (Chairman), Professor J. J. 
HUMMEL (Secretary), Dr. W. H. Perkin, Professor W. J. RUSSELL, 
Captain ABNEY, Professor W. Stroup, and Professor R. MELDOLA. 
(Drawn up by the Secretary.) 
Durine the past year (1898-9) the work of this Committee has been 
continued, and a large number of wool and silk patterns, dyed with 
various natural and artificial violet and grey colouring matters, have been 
examined with respect to their power of resisting the fading action of 
light. 
The general method of preparing the dyed patterns, and the manner 
of exposing them under glass, with free access of air and moisture, were 
the same as already adopted in previous years. 
The thanks of the Committee are again due to Edward A. Hirst, Esq., 
in whose grounds the patterns were exposed, at Adel, near Leeds. 
Each dyed pattern was divided into six pieces, one of which was pro- 
tected from the action of light, while the others were exposed for different 
periods of time. These ‘ periods of exposure’ were made equivalent to those 
adopted in previous years by exposing, along with the pattern, special 
series of ‘ standards,’ dyed with the same colouring matters as were then 
selected for this purpose. The standards were allowed to fade to the 
same extent as those which marked off the ‘fading period’ in previous 
years before being removed, or before removing a set of dyed patterns 
from the action of light. The patterns exposed during the past year are 
therefore comparable, in respect of the amount of fading action to which 
they have been submitted, with the dyes already reported upon. 
The patterns were all put out for exposure on March 12, 1898, certain 
sets being subsequently removed on the following dates: April 20, May 
28, June 27, October 22, 1898 ; April 25, 1899. Of these five ‘periods of 
