Actually, the first printed account of Scheele’s results was in Bergman’s paper
de attractionibus electivis [22]. Bergman gave a clear summary of Scheele’s work:
nitrogen monoxide reacts with “pure air” (oxygen) to generate heat, while only
one-fourth
3 of common air reacts with nitrogen oxide. Heat is a compound of “pure
air” and phlogiston. Pure air can be obtained by heating mercury oxide and supports
combustion and respiration. It has been suggested by Partington that this paper
actually predates Priestley’s book [23]. On the other hand, Cassebaum and Schufle
claim that the printing of the second volume of Nova Acta, including Bergman’s
paper, was actually not finished until 1776, although it has the year 1775 printed on
the title page [24]. This is supported by the preserved correspondence between
Scheele and Bergman, which suggest that Bergman was unaware of oxygen until
early 1776. In reality, this is of little importance, as few seem to have taken notice
of Bergman’s description of oxygen. In fact, the section on oxygen was removed in
the second edition of his essay on elective attractions, published in Bergman’s
collected works in 1783 [25]. It was this edition that was eventually translated to
English; [26] the original edition was not translated until 1968 [27]. The discovery
of oxygen was most commonly attributed to Priestley, and not until Nordenskiöld’s
investigation over a century later, that Scheele’s contribution was more widely
acknowledged. No evidence has been found to back up Lavoisier’s claim [28] of
having discovered oxygen independently of Scheele and Priestley. In conclusion, it
was through the works of Priestley that the world learned of oxygen, but it should
be kept in mind that his ideas of air and combustion were very vague. Scheele made
his discovery earlier and had a much clearer view on the subject than Priestley, but
his theories still had little impact on the progress of chemistry, as Lavoisier already
had made the first step towards our modern concepts of combustion by the time
Scheele’s book appeared. Priestley played the major role in spreading the knowledge of oxygen, but his vague theoretical speculations had no impact. Although
Scheele and Priestley share the credit of having discovered oxygen, it was Scheele
alone who realised that air is a mechanical mixture of oxygen, nitrogen, carbon
dioxide, and various vapours such as water.
Scheele’s book does not have the same logical disposition as the works by
Bergman. It is composed of 97 numbered sections with experiments and theoretical
discussions mixed. There is no concluding remarks or summary, so the reader is
forced to read the whole book in order to get an overview. There is no strict division
into chapters, but subtitles are inserted in the text in a slightly arbitrary manner. The
order in which topics are discussed seem somewhat arbitrary. The book was
probably written in haste, and would have gained much if Scheele would have
planned his writing better or asked Bergman for advice.
Bergman’s preface deals very little with Scheele’s discoveries, but he assured
that Scheele had worked independently, and that the manuscript had been finished 2
years earlier. In a letter to Gahn, Bergman wrote: “I have written a small preface to
the work [i.e. Scheele’s book] on the benefits of chemistry, especially the finer
3
Scheele stated 1/3, so it seems that Bergman had repeated these experiments.
21.3 Scheele’s Book on Air and Fire
287
de attractionibus electivis [22]. Bergman gave a clear summary of Scheele’s work:
nitrogen monoxide reacts with “pure air” (oxygen) to generate heat, while only
one-fourth
3 of common air reacts with nitrogen oxide. Heat is a compound of “pure
air” and phlogiston. Pure air can be obtained by heating mercury oxide and supports
combustion and respiration. It has been suggested by Partington that this paper
actually predates Priestley’s book [23]. On the other hand, Cassebaum and Schufle
claim that the printing of the second volume of Nova Acta, including Bergman’s
paper, was actually not finished until 1776, although it has the year 1775 printed on
the title page [24]. This is supported by the preserved correspondence between
Scheele and Bergman, which suggest that Bergman was unaware of oxygen until
early 1776. In reality, this is of little importance, as few seem to have taken notice
of Bergman’s description of oxygen. In fact, the section on oxygen was removed in
the second edition of his essay on elective attractions, published in Bergman’s
collected works in 1783 [25]. It was this edition that was eventually translated to
English; [26] the original edition was not translated until 1968 [27]. The discovery
of oxygen was most commonly attributed to Priestley, and not until Nordenskiöld’s
investigation over a century later, that Scheele’s contribution was more widely
acknowledged. No evidence has been found to back up Lavoisier’s claim [28] of
having discovered oxygen independently of Scheele and Priestley. In conclusion, it
was through the works of Priestley that the world learned of oxygen, but it should
be kept in mind that his ideas of air and combustion were very vague. Scheele made
his discovery earlier and had a much clearer view on the subject than Priestley, but
his theories still had little impact on the progress of chemistry, as Lavoisier already
had made the first step towards our modern concepts of combustion by the time
Scheele’s book appeared. Priestley played the major role in spreading the knowledge of oxygen, but his vague theoretical speculations had no impact. Although
Scheele and Priestley share the credit of having discovered oxygen, it was Scheele
alone who realised that air is a mechanical mixture of oxygen, nitrogen, carbon
dioxide, and various vapours such as water.
Scheele’s book does not have the same logical disposition as the works by
Bergman. It is composed of 97 numbered sections with experiments and theoretical
discussions mixed. There is no concluding remarks or summary, so the reader is
forced to read the whole book in order to get an overview. There is no strict division
into chapters, but subtitles are inserted in the text in a slightly arbitrary manner. The
order in which topics are discussed seem somewhat arbitrary. The book was
probably written in haste, and would have gained much if Scheele would have
planned his writing better or asked Bergman for advice.
Bergman’s preface deals very little with Scheele’s discoveries, but he assured
that Scheele had worked independently, and that the manuscript had been finished 2
years earlier. In a letter to Gahn, Bergman wrote: “I have written a small preface to
the work [i.e. Scheele’s book] on the benefits of chemistry, especially the finer
3
Scheele stated 1/3, so it seems that Bergman had repeated these experiments.
21.3 Scheele’s Book on Air and Fire
287