Letter from John Dalton to Respected Friend [Peter Crosthwaithe?]

Kendal, 1st mo. 11th 1793


Respected Friend,

I have sent the Journal and a Thermometer herewith; I mean it to pay thee for the Trouble I have given thee in making Observations Etc – If it should be broken, send the Frame and Tube back.- Thou may try the accuracy of the Ther, any day, by getting a Pound or two of Ice, breaking is into small pieces, and mixing it in a Quantity of Water, + they will, if true, stand at the freezing point:- Snow will do also.

Thou should make a Memorandum in the Journal how far the new Bar. Scale is distant from the old one, at the mark 31 inches.- I find that at the Beginning of 90 thou has poured a quantity of Silver into the Bason to raise the Bar. About 2/sixteenths, instead of altering the Scale – and reasoned upon it thus I suppose, that as the Bar. Was wrong 4 sixteenths at 28 it would be wrong 2 sixteenths at 29 ½, and that therefore if it were raised 2 sixteenths the Errors on one side would balance those on the other – this Reasoning is not bad; however putting on a narrow slip of Paper for a new Scale is preferable.- I consider both our Barometers as inaccurate with Respect to the Distance of the Basons and Scales; but this is of little importance provided they be true in other Respects; this only serves to show the relative heights of the places to the Sea, which we can come at better by other Means.- I have therefore in my calculations on thy Bar, taken it for granted that the Distance between the surface of the Bason and the Mark 31 on the old Scale, for the last 3 years, is true; this being admitted, the true Method of correcting for the short Scale is easy and very readily done, as follows: Find the monthly Mean of Scale; deduct if from 31; divide the remainder by 12; the quotient added to the before found Mean, gives the correct Mean; Thus the Mean for Jany 90 by the Journal is 29.788, the correct mean is 29.881 and the like for any particular observation: And for the two former years I make the further constant addition of 2 sixteenths, or rather, 12 decimals.

I would not have thee labour too much with Skiddow considering the Season of the Year; it is not a matter of the greatest Importance to know its Height – and with Respect to the other Mountains I only meant to have their altitudes in round Numbers, as seen from a Place in the Vale, to about 8 points of the compass.

I noted thy paragraph in the Cumberland Paquet we have just about as much Rain here last Year – and Snow on the Night of the 4th Inst.- Thou would do well to examine whether thy gauge be truly level; J. Gough’s and mine were both thrown aside a little last month by the Frost or something; mine to the leeward and his to the Windward: the Consequence was that he beat me surprisingly on windy Days.

I cannot get my Calabash into this Box:- it is but a fractured one also;- I may probably meet with some Opportunity of sending it:- J. Gough heard of that Fish when here, and wished to examine it, but for some Reason or other missed: it is doubtless worthy of a Place in the Museum.

If the Journal comes in a week or Ten Days There will be no Fault.

I must now add a Word respecting Walker.

J. Gough and I are both of Opinion, that if the Paper be sent up under a borrowed Name it will not be inserted; but probably it may if with thy own Name: and that it should be sent nearly as it is, without much Addition of Alteration;-if thou should make Additions respecting the Character of the Museum, Etc, it would look like Ostentation; and if it were under a fictitious Name, most People would judge thee to be the Author, or at least the Instigator of it; besides there is a little Inconsistency in uniting a Piece of Criticism with any Thing of the Nature of an Advertisement.

Upon the whole, therefore, we do not wish to press thee any one way, but to leave it to thy own judgement – yet we think it will be most prudent to send it in thy own Name, and nearly as it is drawn up; or else to suppress it entirely – As to the Paper Man we think it out of the Question; He is so obviously wrong that he has no Ground to stand upon; if we fear anything, it is, that he will be so malicious as to seek for a Handle to call thee to account another way; this indeed may be avoided by using a fictitious Name, but then the Risk falls upon the Publisher, and it is great odds he refuses its insertion.

I am thine respectfully

John Dalton