On this page
-
Text (1)
-
Untitled Article
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software. The text has not been manually corrected and should not be relied on to be an accurate representation of the item.
-
-
Transcript
-
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software. The text has not been manually corrected and should not be relied on to be an accurate representation of the item.
Additionally, when viewing full transcripts, extracted text may not be in the same order as the original document.
Untitled Article
admitted water into it , and found that it was not imbibed by it . But what surprised me more than I can well express , was , that a candle burned in this air with a remarkably vigorous flame , very much like that enlarged flame with which a candle burns in
nitrous air , exposed to iron or liver of sulphur ; but , as I had got nothing like this remarkable appearance from any kind of air besides this peculiar modification of nitrous air , and I knew no nitrous acid was used in the preparation of mercurius calcinatus , I was utterly at a loss how to account for it . ' *
He afterwards obtained the same kind of air by exposing red lead and several other substances to heat , and made a number of well-devised experiments upon its properties . Those who , for the first time , witness the effect of this air upon burning
bodies , will best picture to themselves the emotion and surprise of its discoverer , when he plunged a burning taper into it . The splendour of the flame was niaguificentiy increased , the consumption of the wax was extremely rapid , and the heat evolved much more considerable than in
common air . He found 3 in short , that , in all cases of combustion , the process was infinitely more rapid and perfect in this kind of air , than in the ordinary atmosphere , t and he was thence induced to apply the term dephlogistieated to the gas he had thus obtained .
* jEcr , perl ? nents and Observations on Different Kinds of Air , &c . II . 107 . Birmingham , 1790 . f The following" paragraph , with which Dr . Priestley prefaces his account of the discovery of dephlogisticated air , presents a picture of his mind in regard to the origin of his own researches :
" The contents of this section will furnish a very striking * illustration of the truth of a remark which I have more than once made in my philosophical writings , and which can hardly be too often repeated , as it tends greatly to encourage philosophical investigations - viz . that more is owing to
what we call chance , that is , philosophically speaking , to the observation of events arising from unknown causes , than to any proper design or preconceived theory in this business . This does not appear in the works of those who write synthetically upon these subjects , but would , I doubt not , appear very strikingly in those who
Untitled Article
He regarded it as air deprived of phlogiston , and thus accounted for its eager attraction for that principle which , during combustion , bodies were imagined to throw off . Gn the contrary , he accounted for the
extinction of name by the air discovered by Rutherford , and since termed azote * or nitrogen , + upon the idea that that aeriform fluid was charged or saturated with phlogiston , and he , therefore , called it phlogisticated air . J In enumerating the higher merits
of Dr . Priestley as a discoverer , we must not forget the minor advantages which his ingenuity bestowed upon experimental chemistry . He supplied the Laboratory with many new and useful articles of apparatus , and the improved methods of managing ,
collecting and examining gaseous fluids , were chiefly the results of his experience . He was the first who , with any chance of accuracy , endeavoured to ascertain the relative or specific gravities of the different kinds of air then known ; he observed that
dephlogisticated air was rather heavier , and phlogisticated air somewhat lighter , than that of the atmosphere ; nitrous air he conceived to be nearly of the same specific gravity . His experiments were made by the help of a delicate balance aud exhausted flask .
The influence upon the respiration of animals of a species of air marked by the eminent perfection with which it supports combustion , did not escape Dr . Priestley ' s notice . On applying
to it his test of nitrous air , he found the absorption produced on mixture greater than with atmospheric air ; whence he conjectured its superior fitness for the support of life - , he introduced mice into it . and fbund that
are the most celebrated for their pbilosophical acumen , did tbey write analytically ami ingenuously . " ( E&p . and Obs . II . 103 . ) * From < x and ^ on ? , ct destructive of life . + i . e . Producer of nilric acid .
j Tbe application of deplilogisticated air to obtain intense degrees of beat , and its probable uses in medicine , were subjects wbich did not altogether escape Dr . Priestley ' s attention , and he has alluded to them in the section of tbe work already quoted , relating to its u Properties and Uses . "
Untitled Article
68 O Mr . Branded Estimate of Dr . Priestley ' s Chemical Discoveries .
-
-
Citation
-
Monthly Repository (1806-1838) and Unitarian Chronicle (1832-1833), Nov. 2, 1818, page 680, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/mruc/issues/vm2-ncseproduct2482/page/16/
-