Extract from Thomas Jefferson to Thomas Mann Randolph
|New York April 18. 1790.|
my method is to make two observations a day, the one as early as possible in the morning, the other from 3. to 4. aclock, because I have found 4. aclock the hottest & day light the coldest point of the 24. hours. I state them in an ivory pocket book in the following form, & copy them out once a week.
the 1st column is the day of the month.
the 2d the thermometer in the morning
the 4th do in the evening
the 3d the weather in the morning
the 5th do in the afternoon
the 6th is for miscellanies, such as the appearance of birds, leafing & flowering of trees, frosts remarkeably late or early, Aurora borealis, Etc in the 3d & 5th columns, a. is after: c, cloudy: f, fair: h, hail: r, rain: s, snow. thus c a r h s means, cloudy after rain, hail & snow. whenever it has rained, hailed or snowed between two observations I note it thus, f a r (i.e. fair after rain) c a s (cloudy after snow Etc. otherwise the falling weather would escape notation. I distinguish weather into fair or cloudy, according as the sky is more or less than half covered with clouds.