In the section on air, Bergman gave the account of oxygen that is missing in The
Chemical Lectures of H.T. Scheffer. After discussing gases and vapours, he discussed oxygen (pure air), carbon dioxide (aerial acid) and nitrogen, which he did
not give a name. He was of the opinion that the inner nature of nitrogen was
unknown, but regarded it as “phlogisticated”. Oxygen was consumed by respiration, putrefaction and combustion but Bergman believed in regeneration of oxygen
in nature, and highlighted the role of green plants.
Bergman described hydrogen and the difference between different combustible
gases (hydrogen and methane). Methane or marsh gas was evolved in swamps and
Bergman believed that it collected in the atmosphere where it was ignited by
electricity and gave rise to falling stars and other light phenomena. Hydrogen
sulphide (hepatic air) was composed of sulphur, phlogiston and heat, while sulphur
dioxide (acidic vitriolic air) was composed of phlogiston, heat and sulphuric acid
deprived of water. This is in some sense correct, as sulphuric acid minus water is
sulphur trioxide, which upon reduction gives sulphur dioxide. The other gases
discussed are nitrogen oxide, hydrogen chloride, chlorine, hydrogen fluoride, ammonia and a gas that Bergman calls acetic air evolved on boiling concentrated
acetic acid.
3
11.3 Bergman’s Lectures
In 1782, Spanish chemist and mineralogist Juan José d’Elhuyar (1754–1796) visited Bergman and attended his lectures. d’Elhuyar was later appointed inspector of
mining in Spanish Colombia, and died in Bogotá. In the late 1950s, d’Elhuyar’s
notes of Bergman’s lectures were owned by a descendent to d’Elhuyar in Buenos
Aires and a copy on microfilm was presented to Stig Rydén, who travelled in South
America on the behalf of the Swedish Museum of Ethnography in Stockholm. The
notes were published (in its original French) by chemistry professor Fredga and
Rydén [28], and in English translation by Schufle [29]. On investigating the notes,
Rydén and Fredga found that the notes had been copied at a later date by someone
who was not very familiar with chemistry. Also, neither Bergman nor d’Elhuyar
were native French speakers, in fact, d’Elhuyar’s French was quite poor [28]. This
is important to remember, as it prevents a deeper analysis of the text.
The first part of the lecture deals with acids. It seems that d’Elhuyar only noted
facts which were unfamiliar to him, since neither sulphuric nor carbonic acid are
discussed. Carbonic acid (Chap. 18) was one of Bergman’s favourite topics, and
would definitely be included in the lecture. Perhaps Bergman had already discussed
the topic with d’Elhuyar before the lecture. Most space is devoted to molybdic and
tungstic acid, both recently discovered by Scheele (Chap. 15). It is thus not
3
This seems to be an erroneous observation, and it is difficult to understand which gas it would
correspond to other than acetic acid vapour.
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11 Bergman as a Teacher
Chemical Lectures of H.T. Scheffer. After discussing gases and vapours, he discussed oxygen (pure air), carbon dioxide (aerial acid) and nitrogen, which he did
not give a name. He was of the opinion that the inner nature of nitrogen was
unknown, but regarded it as “phlogisticated”. Oxygen was consumed by respiration, putrefaction and combustion but Bergman believed in regeneration of oxygen
in nature, and highlighted the role of green plants.
Bergman described hydrogen and the difference between different combustible
gases (hydrogen and methane). Methane or marsh gas was evolved in swamps and
Bergman believed that it collected in the atmosphere where it was ignited by
electricity and gave rise to falling stars and other light phenomena. Hydrogen
sulphide (hepatic air) was composed of sulphur, phlogiston and heat, while sulphur
dioxide (acidic vitriolic air) was composed of phlogiston, heat and sulphuric acid
deprived of water. This is in some sense correct, as sulphuric acid minus water is
sulphur trioxide, which upon reduction gives sulphur dioxide. The other gases
discussed are nitrogen oxide, hydrogen chloride, chlorine, hydrogen fluoride, ammonia and a gas that Bergman calls acetic air evolved on boiling concentrated
acetic acid.
3
11.3 Bergman’s Lectures
In 1782, Spanish chemist and mineralogist Juan José d’Elhuyar (1754–1796) visited Bergman and attended his lectures. d’Elhuyar was later appointed inspector of
mining in Spanish Colombia, and died in Bogotá. In the late 1950s, d’Elhuyar’s
notes of Bergman’s lectures were owned by a descendent to d’Elhuyar in Buenos
Aires and a copy on microfilm was presented to Stig Rydén, who travelled in South
America on the behalf of the Swedish Museum of Ethnography in Stockholm. The
notes were published (in its original French) by chemistry professor Fredga and
Rydén [28], and in English translation by Schufle [29]. On investigating the notes,
Rydén and Fredga found that the notes had been copied at a later date by someone
who was not very familiar with chemistry. Also, neither Bergman nor d’Elhuyar
were native French speakers, in fact, d’Elhuyar’s French was quite poor [28]. This
is important to remember, as it prevents a deeper analysis of the text.
The first part of the lecture deals with acids. It seems that d’Elhuyar only noted
facts which were unfamiliar to him, since neither sulphuric nor carbonic acid are
discussed. Carbonic acid (Chap. 18) was one of Bergman’s favourite topics, and
would definitely be included in the lecture. Perhaps Bergman had already discussed
the topic with d’Elhuyar before the lecture. Most space is devoted to molybdic and
tungstic acid, both recently discovered by Scheele (Chap. 15). It is thus not
3
This seems to be an erroneous observation, and it is difficult to understand which gas it would
correspond to other than acetic acid vapour.
170
11 Bergman as a Teacher