As you have been so good as to forgive my long Delay of writing to you and answering your always agreable Letters, I shall not now trouble you with the Apology I had written on that head in one of my Pieces of Letters never finish’d.

Supposing the Fact, that the Water of the Well at Bristol is warmer after some time pumping, I think your manner of accounting for that increas’d Warmth very ingenious and probable. It did not occur to me, and therefore I doubted of the Fact.

You are, I think, quite right in your Opinion, that the Rising of the Tides in Rivers is not owing to the immediate Influence of the Moon on the Rivers. It is rather a subsequent Effect of the Influence of the Moon on the Sea, and does not make its Appearance in some Rivers till the Moon has long pass’d by. I have not express’d myself clearly if you have understood me to mean otherwise. You know I have mention’d it as a Fact, that there are in some Rivers several Tides all existing at the same time; that is, two, three, or more, Highwaters, and as many Low-Waters, in different Parts of the same River, which cannot possibly be all Effects of the Moon’s immediate Action on that River; but they may be subsequent Effects of her Action on the Sea.

In the enclos’d Paper you will find my Sentiments on several Points relating to the Air and the Evaporation of Water. It is Mr. Collinson’s Copy, who took it from one I sent thro’ his Hands to a Correspondent in France some Years since; I have, as he desired me, corrected the Mistakes he made in transcribing, and must return it to him; but if you think it worth while, you may take a Copy of it: I would have sav’d you any trouble of that kind, but had not time.

Some day in the next or the following Week, I purpose to have the pleasure of seeing you at Wanstead; I shall accompany your good Mama there, and stay till the next Morning, if it may be done without incommoding your Family too much. We may then discourse any Points in this Paper that do not seem clear to you; and taking a Walk to some of Lord Tilney’s Ponds, make a few Experiments there to explain the Nature of the Tides more fully. In the mean time, believe me to be, with the highest Esteem and Regard, my dear good Girl, your sincerely affectionate Friend