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.

    74/966 (page 72)
    3. ‘That the strength of the affinity be greater than any counteracting causes which may be present. 321, The principal counteracting causes of chemical union are, vid . 1. The attraction of aggregation ; 2. Gaseous repulsion of particles ; 3. Affinities for other substances. | 322. The attraction of aggregation is overcome by means of ; ) 1, Mechanical division. | __ 2. The action of caloric. - . 323. ‘The gaseous repulsion of particles is prevented, from operating, by presenting the bodies to each other before they have assumed the form of gas, or, as it is called, in their nascent state, or by flame, the electic spark or sudden compression, which probably operate by forcing the parti- cles within the sphere of attraction. 324. The means to be employed for overcoming the action of other affinities will be treated of under Decomposition. 325. Combination is facilitated by increasing the points of actual contact, or by rendering them closer, 1. By mechanical agitation ; | 2. By condensation ; compression. 326, The processes employed for producing combination may, be considered, 1. With regard to the nature of the substances combi- ned; and, Niet : 2. To the nature of the ‘compound produced. | 327. There are many instances of bodies of all. forms of aggregation entering into chemical union with other bodies of the same form, or of different forms, and producing com- pounds of various forms of ageregation. ' ; 328. The combination of gases with each other, in some instances, takes place when simply mixed together: thus ni- trous. and oxygen gases combine as soon as they come into contact; im other instances, it is necessary to elevate their temperature to a degree sufficient for their inflammation, ei- ther by means of the electric spark, or the contact ofan igs nited body, as in the combination of oxygen gas with hydro- gen. gas, ‘or by an equivalent degree of pressure. 329. When gases combine with each other, there is ge- nerally a considerable diminution of bulk, and not unfre- quently they are condensed into a liquid or solid form. But when the combination-is effected by ignition, a violent ex-