10.1 Scheele’s Research in Stockholm
It has been said that the time in Stockholm was a disappointment for Scheele since
he had to work in the shop, rather than the laboratory [8]. It is quite clear, however,
that Scheele carried out important research in Stockholm, but perhaps he had less
time for experiments in Stockholm than in Malmö. It is also quite probable that
Scharenberg was less forgiving and supporting compared to Kjellström. According
to tradition, it was in the window of the Raven Pharmacy that Scheele studied the
action of solar light on silver chloride, although the results were not published until
1777 [9]. This was the first photochemical experiment involving a pure compound,
and the first step towards photography (Fig. 10.2).
Scheele seems to have collaborated with Retzius, who many years later wrote to
Scheele’s biographer Wilcke that “none of us made any experiments without
communicating them with each other” [10]. It was in Stockholm that Scheele
discovered the acidic properties of carbon dioxide (Chap. 18) and according to
Oseen, it may have been in Stockholm rather than in Uppsala that Scheele discovered oxygen (Sect. 21.1).
The isolation of tartaric acid became the first of Scheele’s discoveries to be
published, but it is impossible to determine to what extent Retzius contributed to the
discovery. It is believed that Scheele, probably already in Malmö, had found a way
to isolate tartaric acid from potassium hydrogen tartrate (cream of tartar). Retzius
was now granted 300 copper dalers for experiments on cream of tartar [11] and the
results of his experiments were published in the July to September 1770 issue of the
Transactions, i.e. after Scheele’s move to Uppsala. This paper, On cream of tartar
and its acid [12] describes the isolation of tartaric acid and is, probably to a large
extent, based on experiments by Scheele. After Scheele’s death, Retzius wrote to
Wilcke
“The discovery of tartaric acid is the fruit of our common labour, although I, by agreement,
undertook the experiments with it, while Scheele performed a succession of experiments
that formed the base of his beautiful book on air and fire”.
Although the paper on tartaric acid is written by Retzius
2 , he did not take sole
credit for the discovery and it is in this paper that Scheele’s name first appears in
print: “These experiments I related to Mr Carl Wilhelm Scheele (a fast and curious
pharmaciæ studiosus)”. Potassium hydrogen tartrate is only sparingly soluble in
water (0.37 g per 100 ml at 20 °C) and is deposited in wine barrels on storage.
Scheele found that the addition of calcium carbonate gave calcium tartrate, with
even lower solubility. Treating calcium tartrate with sulphuric acid gave calcium
sulphate (gypsum), which could be filtered off leaving tartaric acid in solution.
2
The eighteenth-century papers in the Transactions typically had a single author.
156
10 Scheele Moves to Stockholm
It has been said that the time in Stockholm was a disappointment for Scheele since
he had to work in the shop, rather than the laboratory [8]. It is quite clear, however,
that Scheele carried out important research in Stockholm, but perhaps he had less
time for experiments in Stockholm than in Malmö. It is also quite probable that
Scharenberg was less forgiving and supporting compared to Kjellström. According
to tradition, it was in the window of the Raven Pharmacy that Scheele studied the
action of solar light on silver chloride, although the results were not published until
1777 [9]. This was the first photochemical experiment involving a pure compound,
and the first step towards photography (Fig. 10.2).
Scheele seems to have collaborated with Retzius, who many years later wrote to
Scheele’s biographer Wilcke that “none of us made any experiments without
communicating them with each other” [10]. It was in Stockholm that Scheele
discovered the acidic properties of carbon dioxide (Chap. 18) and according to
Oseen, it may have been in Stockholm rather than in Uppsala that Scheele discovered oxygen (Sect. 21.1).
The isolation of tartaric acid became the first of Scheele’s discoveries to be
published, but it is impossible to determine to what extent Retzius contributed to the
discovery. It is believed that Scheele, probably already in Malmö, had found a way
to isolate tartaric acid from potassium hydrogen tartrate (cream of tartar). Retzius
was now granted 300 copper dalers for experiments on cream of tartar [11] and the
results of his experiments were published in the July to September 1770 issue of the
Transactions, i.e. after Scheele’s move to Uppsala. This paper, On cream of tartar
and its acid [12] describes the isolation of tartaric acid and is, probably to a large
extent, based on experiments by Scheele. After Scheele’s death, Retzius wrote to
Wilcke
“The discovery of tartaric acid is the fruit of our common labour, although I, by agreement,
undertook the experiments with it, while Scheele performed a succession of experiments
that formed the base of his beautiful book on air and fire”.
Although the paper on tartaric acid is written by Retzius
2 , he did not take sole
credit for the discovery and it is in this paper that Scheele’s name first appears in
print: “These experiments I related to Mr Carl Wilhelm Scheele (a fast and curious
pharmaciæ studiosus)”. Potassium hydrogen tartrate is only sparingly soluble in
water (0.37 g per 100 ml at 20 °C) and is deposited in wine barrels on storage.
Scheele found that the addition of calcium carbonate gave calcium tartrate, with
even lower solubility. Treating calcium tartrate with sulphuric acid gave calcium
sulphate (gypsum), which could be filtered off leaving tartaric acid in solution.
2
The eighteenth-century papers in the Transactions typically had a single author.
156
10 Scheele Moves to Stockholm