Details
HALES, Stephen (1677-1761). Autograph letter signed to an unidentified correspondent ('Sir'), Teddington, 29 August 1737, 2 pages, 8vo, integral leaf addressed to 'Dr Nesbit in Basinghall Street/London', endorsed in a later hand below the date 'Nesbitt Aug. 7, 1794' and on the address panel 'J. Nesbit 1795' (slightly darkened, small splits in folds of second leaf).
The leading English scientist of his day sends precise instructions for testing the quality of the water of Islington. 'As you have formerly given me leave I take the liberty to apply to you once more to make an experiment on the Islington water, viz: to take 7 or 8 clear quart bottles, and fill them at the spring; & drop into one 8 drops of ol:sulph: & into the others 7, 6, 5, 4, 3, 2 and one drops. When the Bottles have stood an hour so as to give time (with a little shaking) for the ol:sulph: to mix uniformly with the water, then pour some of each Bottle into equal size glasses or viols [sic], putting a little powdered Galls into each Glass. observe w[hi]ch gives no tincture, w[hi]ch a weak one, & w[hi]ch strongest.'
The experiment demonstrates that the number of drops of oleum sulphate required to preserve the water varies in proportion to its 'foulness'. Hales refers to his tests on water at Claremont where it is very pure, 'Tunbridge water requiring three drops', and asks Nesbit, 'as Islington water has the name of a very impure water', to conduct a further test by weighing a flask before and after evaporation, mentioning that its foulness is blamed by physicians for 'very bad cholicky effects'.
The Reverend Stephen Hales, a scientist without formal training, was the founder of plant physiology. His experiments were fundamental to the understanding of pneumatic chemistry and he also made significant advances in the understanding of the circulation. He was a pioneer in public health, an early advocate of the importance of ventilation, and in the present letter refers to his important experiments in methods of keeping drinking water sweet. Hales successfully combined his scientific work with the care of his parish at Teddington, where he was allowed to use plants from the nearby royal gardens at Hampton Court for his experiments. In 1737 he was particularly interested in the properties of chalybeate waters (from areas with iron ore deposits). The experiments on 'chalybeate or steel waters' which he has completed at the time of the letter ('I have now in a manner done with these experiments on chalybeate waters') were published in 1739.
The leading English scientist of his day sends precise instructions for testing the quality of the water of Islington. 'As you have formerly given me leave I take the liberty to apply to you once more to make an experiment on the Islington water, viz: to take 7 or 8 clear quart bottles, and fill them at the spring; & drop into one 8 drops of ol:sulph: & into the others 7, 6, 5, 4, 3, 2 and one drops. When the Bottles have stood an hour so as to give time (with a little shaking) for the ol:sulph: to mix uniformly with the water, then pour some of each Bottle into equal size glasses or viols [sic], putting a little powdered Galls into each Glass. observe w[hi]ch gives no tincture, w[hi]ch a weak one, & w[hi]ch strongest.'
The experiment demonstrates that the number of drops of oleum sulphate required to preserve the water varies in proportion to its 'foulness'. Hales refers to his tests on water at Claremont where it is very pure, 'Tunbridge water requiring three drops', and asks Nesbit, 'as Islington water has the name of a very impure water', to conduct a further test by weighing a flask before and after evaporation, mentioning that its foulness is blamed by physicians for 'very bad cholicky effects'.
The Reverend Stephen Hales, a scientist without formal training, was the founder of plant physiology. His experiments were fundamental to the understanding of pneumatic chemistry and he also made significant advances in the understanding of the circulation. He was a pioneer in public health, an early advocate of the importance of ventilation, and in the present letter refers to his important experiments in methods of keeping drinking water sweet. Hales successfully combined his scientific work with the care of his parish at Teddington, where he was allowed to use plants from the nearby royal gardens at Hampton Court for his experiments. In 1737 he was particularly interested in the properties of chalybeate waters (from areas with iron ore deposits). The experiments on 'chalybeate or steel waters' which he has completed at the time of the letter ('I have now in a manner done with these experiments on chalybeate waters') were published in 1739.
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