OILS. 263 
it is doubtful whether the cleansing action upon the boilers can be 
attributed to acid in solution. In most instances scale will be 
lessened during the first application, but in others, where the scale 
is hard, it does not begin to move for six weeks or more. The 
extract does not act suddenly on the scale, but on close observa- 
tion good results will be immediately seen. The liquid may be 
put in through the manhole, feed-pipe, safety-valve, condenser, or 
hot-well. After it is put in no new scale will form, and the iron 
will cease to rust.”’ 
6. Eucalyptus amygdalina, Zadc//.; N.O., Myrtacex, B.FI. iii., 
202. 
“Peppermint.” ‘Mountain Ash.” (For the numerous botanical 
synonyms and vernacular names of this tree, see ‘‘ Timbers.’’) 
This species is far richer in oil than any other Eucalypt, the 
average yield from the leaves being demonstrated by Mr. Bosisto 
at about 3 percent. The distilled oil is pale-yellow, thin, of rather 
pungent cajeput-like odour, resembling, but coarser than, lemons; 
of a cooling, but afterwards bitter taste, of specific gravity at 15°, 
.881 (later experiments give .856 for rectified, and .865 for non- 
rectified), boiling point 329° to 370°F., and it deposits stearoptene 
at low temperatures (18° which melts at 3°). It dissolves gutta- 
percha readily, and may be used in lamps like petroleum, with the 
important advantages of greater illuminating power, pleasant odour, 
and non-liability to explosion, but it is much more expensive than 
the latter. (Mueller.) Some of this oil was exhibited at the 
London International Exhibition of 1862. The price quoted was 
six shillings per gallon, and the jurors proceed to remark :— 
“ Three ounces of the oil were sufficient to scent very strongly 
eight pounds of soap, at a cost of about one farthing per pound. 
The perfume produced by this oil alone would, however, be con- 
sidered by some more peculiar than agreeable, and we obtained a 
much better result by combining it in a second experiment with 
oils of cassia, cloves, and lavender, which mixture yielded a very 
pleasant fragrance.” 
The ‘‘Oil of Eucalyptus” in general use, is frequently obtained 
from £. amygdalina, and not from £. globu/us, being more 
