Santiago de Chile, March 28, 1790
You can imagine how gratified and honoured I am by the part you played in my recent promotion to Ship’s Captain. Your letter reached me in this capital, whose situation, at the foot of the Andes and above the lovely valley of the Mapocho, has at one and the same time all one could desire of beauty and majesty. We will produce a map or chart of this valley with various perspective views; I am working on a series of triangulations as far as Valparaiso, where our observatory is located; and in this task we are constantly working with the southern celestial catalogue, in regard to which I hope that astronomers will readily accept us as proficient, in so far as we have much to insert and correct. I will indicate to both my brother and friend Belmonti where they should direct the replies to these letters, and forgive me, most esteemed Marquis, for being so forward as to beg you to honour me by making our correspondence as frequent as possible.
We will not put the work of this year in order until we are in Lima, in consequence of which our stay there will be longer. From there I will have the honour to write to you at length, as to other learned people in Europe, on the various principal subjects of our commission, concerning hydrography and astronomy as much as physiology, botany and natural history. I hope you received my letter from the port of Montevideo; we wrote a the same time to the astronomers of Brera, bringing them up to date on our various observations; by now, our method of employing the six marine chronometers we have between the two corvettes, and which we constantly reset to a single time by means of daily equations deduced from comparisons of their readings, provides us with longitudes as reliable as those derived from direct celestial observation. The lunar distances are usually of the order of a few minutes, and never exceed half a degree of difference.
Here then is roughly the state of our commission, in which you have had the goodness to participate to such an extent. May Heaven permit us to complete it in peace. An extensive war would ruin us all. I conclude with my desire for your highly-valued advice and friendship, and by confirming myself ...
Updated: June 5, 2018