I did not receive your Favour of the 24h Decr. untill last post. I immediately looked out for a Thermometer and obtained one which appears very sensible as to Heat or Cold, tho’ it is so constructed that I cannot ascertain the Accuracy of the Division by plunging it in boiling water; This appears of Consequence especially when we keep correspondent Observations. I shall observe the Time you mention, and send at present, as it may be some Gratification, on Account of the Severity of the Season my Morning Observations from the 16h. untill this Date. Viz. 14°. 16½. 26°. 38°. 18°. 18°, 25°. In order to observe the greatest Cold, I expose the Thermometer to the Night Air. It either stands out all Night, or lies in an open window. The remainder of the Day it is also as much exposed as it prudently can be, on Account of the Danger of meeting with some Accident—for it is borrowed. I Mention this, because, both ought to be treated in the same Manner. I wish we had [a] Barometer but there is no Possibility of getting one here at present. The British robbed me of my Thermometer and Barometer. We have sent to England and expect a Return by this Spring.

I am much obliged to you for your Goodness in communicating Accounts of such new Books as deserve attention. I have never seen Crawfords, nor indeed heard of it before. But will send for it by the first opportunity. His Theory appears to be altogether new and if well supported by Experiment will introduce philosophical Revolution in that Part of Physics. I think however that Hamilton in his ingenious Treatise on Vapours has led the way to this Doctrine but have not the Book by me to determine at present.

We have availed ourselves of the Informat[ion] you gave concerning the Encyclop. Meth: and have put a Bill of ⅌50 11s. in the Hands of a Merchant so as to have what is already compleated, imported by Spring, and the remainder as soon as finished. I hope to have the best Edition for that Sum.

I think you have adopted an excellent, as well as a very short Method of confuting those Flimsy Theorists, as you justly call them, by sending both Rittenhouse and his Orrery. to Europe.

You have no Doubt observed the Comet which made its Appearance here last Friday Evening for the first Time. The Cloudiness of the Evenings prevented Observations till last Night and the Night before. Its Situation is near, i, in the Piscis Australis. I shall endeavour to trace it’s Progress and will send you the Result.

Be pleased to continue your Favours, for which I am really much indebted, and beleive me to be with the greatest Regard Yr. Sevt. & Friend,