James Dinwiddie (astronomer)

James Dinwiddie (born 8 December 1746 in Dumfries – died 19 March 1815 in Pentonville) was a Scottish physicist, astronomer, inventor and natural philosopher.

In his lectures he demonstrated experiments, instruments and emphasised the use of mathematical principles involved in physical laws and gave examples to support his view:[1] ...When Dr. Black pointed out a variety of double exchanges, and arranged them in a convenient order, he was only a natural historian; but when he came to investigate the immediate cause, and assert the nature of the power which produces the double exchange, he was obliged to employ the property of number and figure.

In short, gentlemen, without a moderate share of mathematical knowledge, you can expect only a schoolboy's acquaintance with natural philosophy, resembling those religionists who take up their authority on the opinion of their priests, and neither can give a reason for what they think they believe, nor apply it to any good purpose in life...Dinwiddie, however, earned little.

When Charles Spalding, the inventor of a diving bell and fellow experimenter, was killed in 1783 in an underwater operation, Dinwiddie attempted to examine the cause of the accident.

He used a technique to make silk airtight and ballooned from Bristol to Waterford while forgetting to pay his rent back in Dublin and nearly losing all his equipment which were to be sold off by the owner.

He received an honorary Doctor of Law degree in 1792 from the University of Edinburgh and he was invited to join the embassy of Lord Macartney to China in 1792-93 where he was to demonstrate science and especially astronomy, a diving bell and a balloon for the Chinese emperor.

The astronomical instruments failed to impress the Chinese, unlike a German-made planetarium device known as the Weltmaschine designed by Philipp Matthäus Hahn.

[2] Returning from China, Dinwiddie met Sir John Shore, Governor-General of Bengal, stayed on in Calcutta and continued his researches.

In August 1795 Dinwiddie was appointed to assist the Board of Trade on matters of science for a salary of 500 rupees a month for a year; but this was not extended.

Dinwiddie advised the East India Company, prepared the chemists kit carried by Francis Buchanan for his survey of Mysore and manufactured nitrous acid for use in the hospital at Calcutta.