Volume 2

The Edinburgh new dispensatory containing 1. The elements of pharmaceutical chemistry. 2. The materia medica ... 3. The pharmaceutical preparations and compositions. Including translations of the London pharmacopoeia of 1825 ... Edinburgh pharmacopoeia ... 1817; Dublin pharmacopoeia ... 1807 / By Andrew Duncan.

  • Duncan, Andrew, Jun., 1773-1832
Date:
1826
Catalogue details

Licence: Public Domain Mark

Credit: The Edinburgh new dispensatory containing 1. The elements of pharmaceutical chemistry. 2. The materia medica ... 3. The pharmaceutical preparations and compositions. Including translations of the London pharmacopoeia of 1825 ... Edinburgh pharmacopoeia ... 1817; Dublin pharmacopoeia ... 1807 / By Andrew Duncan. Source: Wellcome Collection.

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    of solution. 348. The apparent solution of a fluid in the atmosphere is termed Spontaneous evaporation. It is. promoted by ex- posing a large surface, by frequently renewing the air in con- tact with the surface, and by increase of temperature. 349. The quickness with which fluids evaporate is in.pro- portion to the elasticity of their vapour, and this is sometimes so great as to be a source of much inconvenience. It ap- pears that the nature of the covering by which they are at- tempted to be confined has considerable influence, and that it allows those vapours to pass most readily through it. with which it has affinity. 350. Some salts have so strong an affinity for water, that they attract it from the atmosphere in sufficient quanti- ty to dissolve them. ‘They are said to deliquesce. 351. In old pharmacy, deliquescence was used as the means of obtaining a strong solution of some saline bodies ; and, according to the Dublin Pharmacopeia of 1807, the Aqua subcarbonatis kali is still made in this fortuitous way ; which, from its oiliness, was formerly called Olewm tartari per deliquium. ; 352. Deliquescent salts must be kept in a warm dry place ; some, as muriate of lime, attract moisture from the driest air, and must be kept in very closely stopped bottles. Ad- vantage is taken of this property in some pharmaceutic pro- cesses; as in the rectification of alcohol or ether. 353. Other salts,.on the contrary, retain their water of crystallization with so weak a force, that the atmosphere at- tracts it from them, so that they crumble into powder. These are said to effloresce. FE fflorescence, in this case, is owing to the evaporation of the water of crystallization, and hence it has been proposed to term it Deaquescence, to distinguish it from another kind of efflorescence, which. takes. place in iron-clay-slate, and on new plastered walls, which is owing to the shooting of acicular crystals from the absorp- tion of water of crystallization. 354. Deaquescence is employed as a pharmaceutical pro- cess in the preparation of the sulphas sode siccatum, and it is promoted by exposing a large surface, and by a free cur- rent of warm dry air. 355. Solution is either total or partial. Total solution takes place when the solvend is of a homogeneous nature, and is entirely dissolved if the menstrunm be used in suffi- gating Dear