Reference numberAP/27/23
TitleUnpublished paper, 'On the ashes of wheat' by William Sharp
Date9 April 1845
DescriptionSharp shares the results of experiments undertaken with the ultimate view of ascertaining with exactness what quantity of inorganic matter is removed from the soil by the seeds of a crop of wheat. Sharp first inquires what is the average amount of the inorganic or incombustible portion of a given quantity of wheat; a question to which no satisfactory answer has yet been given. The result of the author’s experiments is that wheat yields, by slow combustion, a residue of from 1 1/2 to 1 3/4 percent. He then proceeds to determine by experiment the degree in which this result is influenced by previous drying at different temperatures, varying from 230° to 260° Fahrenheit, and finds that a heat of 245° is not sufficient to expel all the moisture contained in wheat; for while the loss of weight is then about 8 percent, by a heat of 260°, the amount of this loss is 10 percent. When the heat is so great as to occasion decomposition, the saline matter contained in the wheat fuses, and a portion of the carbon becomes so entangled or firmly adherent to it, as to be incapable of separation by burning. Hence Sharp recommends that the wheat subjected to these experiments should be dried at a low temperature, such as that of a room in summer, and be allowed to remain a few days under its influence. Sharp tried the effect of the addition of nitric acid, with a view to save time by accelerating the combustion; but found that the results could not be relied upon when this plan was adopted, and he was therefore obliged to relinquish it. He next directed his inquiries to the ascertaining whether the quantity of inorganic matter was in proportion to the specific gravity of the grain, that is, to its weight per bushel; and this he found in general to be the case. The conclusion he deduces from this investigation is, that the mean amount of inorganic matter removed from the soil by the grain of a crop of wheat is exactly one pound per acre.

Marked on back as 'Archives 5 June 1845 S H C [Samuel Hunter Christie]'.

Subject: Chemistry

Received 24 April 1845.

Written by Sharp at Humber Bank House, Hull [England].

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 5 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'On the ashes of wheat'.
Physical descriptionInk and graphite pencil on paper
Digital imagesView item on Science in the Making
Access statusOpen
Related materialDOI: 10.1098/rspl.1843.0045
Related records in the catalogueMC/4/66
Fellows associated with this archive
NA2932Sharp; William (1805 - 1896)1805 - 1896
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