Copy 1
The naturalist's and traveller's companion, containing instructions for discovering & preserving objects of natural history and for promoting inquiries after human knowledge in general / [Anon].
- John Coakley Lettsom
- Date:
- 1774
Licence: Public Domain Mark
Credit: The naturalist's and traveller's companion, containing instructions for discovering & preserving objects of natural history and for promoting inquiries after human knowledge in general / [Anon]. Source: Wellcome Collection.
56/128 page 30
![. C 30 ] Many of thofe fprings called acidulas, received this name from the mephitic air we have already mentioned. If this acid be prefent, it may be difcovered by an infufion of fyrup of violets, or by an infufion of lacmus, or archil ($0), which are turned of a brighter or reddifh color by it. This acid may be detedted alfo by a folution of lead in the nitrous acid ; the folution fhould be fully faturated. The nitrous acid uniting with calcareous earth, or foffil alkali, falls in a white fediment, while the vitriolic acid combines with the lead. b. In its volatile fulphureous date. (See page 32*) 2. An alkali is alfo very feldom found in water in its proper date. a. When a foffil alkali is prefent, it is more nicely detedled by the fyrup of violets, or infufion of lacrnus, than the former, thefe being turned green by the lead portion of alkali. If a con- fiderable quantity of alkali were combined with the water, it might be precipitated by a folution of calcareous earth, or by acids. b- A volatile alkali may be didinguifhed by a folution of corrofive fublimate mercury in water, or in the nitrous acid, the alkali rendering the folution white, a precipitation of a white powder ervfucs; but no change is produced, when the alkali is the fixed or foffil, or if any, the mer¬ cury will be precipitated in an orange, brown, (w ) This is fo nice a teft, that even mephitic air is apt to give it rather a brighter color. Oince the firft edition. Dr. Prieftley makes a hmilar ob- fervation on the authority of his correlpondent M. Bregman of Upfal. Phiiofophica! Tranfaftions, Vol, LXII. 1773. or](https://iiif.wellcomecollection.org/image/b30511495_0001_0056.jp2/full/800%2C/0/default.jpg)
