In origin of ‘Indian summer’ and French ‘l’été sauvage’, I have explained how the earliest instances of Indian summer and of the corresponding French term l’été sauvage provide clues as to the origin of the English term; these early instances are from texts written in the 1770s by a Frenchman known as J. Hector St. John de Crèvecœur (born Michel-Guillaume Jean de Crèvecœur – 1735-1813)—cf. also European precursors of the American ‘Indian summer’.
Partially based on quotations from Origin of the phrase “Indian summer”, by Matthew R. Halley, published in Notes and Queries (Oxford University Press) of September 2017, the following presents 18th-century instances of Indian summer from texts posterior to those written by Crèvecœur. The quotations from 1790 and 1794 are from diaries: the term Indian summer was evidently familiar to their authors, and they did not explain it, probably because those diaries were intended for their eyes only. In the text written in 1798, Indian summer is curiously applied to a climatic phenomenon occurring in January. Finally, Indian summer is used figuratively in the poem dating from 1791.
The term Indian summer appeared in three diary entries written in October 1790 in present-day Indiana by Josiah Harmar (1753-1813), officer in the United States Army during the American War of Independence (1775-83) and the Northwest Indian War (1785-95):
source: General Harmar’s Expedition, by Basil Meek, published in the Ohio Archaeological and Historical Quarterly (volume 20 – 1911):
Thursday, Octr. 21st-Fine weather-Indian summer.
Saturday, Octr. 23ᵈ-Indian Summer.
Sunday, Octr. 31st-Fine, clear weather-Indian summer.
Another early instance of Indian summer appears in the journal of Ebenezer Denny (1761-1822), officer in the United States Army during the American War of Independence and the Northwest Indian War, under the date of 13th October 1794, when he was near Erie, Pennsylvania:
Pleasant weather. The Indian summer here. Frosty nights. The creek begins to fall.
In a letter that he wrote from Hartford, Connecticut, on 7th June 1798, to Dr E. H. Smith, Mason Fitch Cogswell (1761-1830), American physician, describing the preceding winter there, used Indian summer to designate “a week or fortnight of warm weather which generally takes place about the middle of January”—so far as I know, this is the only use of Indian summer in this sense:
from The Medical Repository (volume 2 – New York, 1799):
About the beginning of January the weather softened considerably, and continued mild for several days. Most people supposed the Indian summer was approaching, (a week or fortnight of warm weather which generally takes place about the middle of January), but, instead of this, there succeeded to these pleasant days a delightful fall of snow, about a foot in depth, which was bound down by an incrustation of hail, and prevented from blowing in heaps by the winds which followed.
1791: figurative use
The term Indian summer was used figuratively in a poem published in the National Gazette (Philadelphia, Pennsylvania) of Thursday 17th November 1791:
The PRUDENT PHILOSOPHER.
[Occasioned by the conduct of some gentlemen, at the conflagration of a certain southern Court-House, during the sessions.]
WHEN from the dome where lawyers spoke,
Issued the mingled flame and smoke,
Marcella at her window sate,
Gazing towards the Dome of State—
That cost the laborer many a tear—
That ne’er would be rebuilt—that’s clear;
And thrice she sigh’d, and smote her breast
To see their squire-ships so distrest;
To see in such a little while
To ashes turn’d so fine a pile!
Meanwhile avoiding pump and pail,
(For what could one man’s help avail?)
Fearing to hurt his tender hand,
Should he amongst the vulgar stand,
Where buckets fly and engines play,
Where slaves must work, and masters may;
Philander to her chamber came,
Thus comforting the tearful dame:
“Behold (said he) my lady fair
How vain these mortal buildings are!
’Tis madness—madness—all things snow
To set our hearts on things below;
(Thank heaven for all its stores of grace,
Our Treasure’s in a safer place:)
But thus the pride of man shall bend;
The gods such fabrics only lend;
Whether contriv’d of brick or stone,
They hardly can be call’d our own:
What time might spare the flame destroys,
To heaven such fabrics are but toys;
Life is a spark from Vulcan stole,
The Indian summer of the soul:
And we ourselves, with years oppress’d,
In time, shall sink among the rest.”