By means of a piece of stretched rubber tubing, this crucible is supported in the mouth of an ordinary funnel which is connected with an exhausting apparatus; and water holding in suspension fine scrapings of asbestos, purified by boiling with strong hydrochloric acid and washing with water, is run through it, so that the perforated bottom is covered with a layer of felted asbestos.
[The movements of camphor scrapings referred to above afford a useful test of the condition of a water surface.
If the contamination exceed a certain limit, the scrapings remain quite dead.
" The Chinese recognize the following grades of opium: (I) ' raw opium,' as imported from India; (2) ' prepared opium,' opium made as above; (3) ' opium dross,' the scrapings from the opium pipe; this is reboiled and manufactured as a second-class prepared opium; a Chinese doctor stated lately at a coroner's inquest on a case of poisoning that it was more poisonous than the ordinary prepared opium; (4) ' nai chai ' (opium dirt), the insoluble residue left on exhausting the raw opium thoroughly with water.
It has been suggested that the above-mentioned callosities or " chestnuts " on the limbs of horses are vestigial scent-glands; and it is noteworthy that scrapings or shavings from their surface have a powerful attraction for other horses, and are also used by poachers and burglars to keep dogs silent.