The reason of your having no sooner received the Quotation from Celsus is, that I wished to employ my very first leisure in looking in several other ancient books for passages to the same purpose, and to send you all together. But Mr. Keir7 having told me of your desire to see that immediately, you have it almost alone.

In the article de Tabe in his third book, treating of the cure He says “cavendae destillationes, ne, si quid cura levarit, exasperent; ob idem vitanda cruditas, simulque et Sol, et frigus.” Here indigestion seems to be reckoned the principal cause. If you have not attended to that particular before, you may be surprized to find Sunshine among the causes of colds, but such is the doctrine of all the Ancients. A passage about the instruments of cure in coughs may perhaps amuse you “Utilis etiam in omni tussi est peregrinatio, navigatio longa, loca maritima, natationes.”8

From several things in Zenophon and in Plato, the prevailing opinion in their time seems to have been that what we now commonly call colds and catarrhs arose almost solely from excess and indolence. On this account Zenophon says that in Persia in the days of Cyrus, to spit or to blow a nose was infamous. Plato often commends simple spare diet, but in one place, he says it prevents all catarrhs. Whether he means precisely what we call catarrhs however, in that passage, may be doubted.

I do not recollect any absolutely express testimony in your favor from Hippocrates. Mucus (of the Nose) and Saliva he judges to be signs of repletion, and he maintains that persons who drink and eat sparingly are free from diseases occasioned by moisture. Abundance may be found in Galen to your purpose. A modern author, who ought to have understood this subject, for he has written so great a book about catarrhs that you had better have 20 colds than read it, is entirely of your opinion. Illa, illa, inquam cibi potusque abundanter citat catarrhos. Eosdem abigat frugalitas et labor.... Ut ex luxu et otio nascuntur catarrhi, ita horum medecina est in sobrietate, in continentia, in exercitationibus corporis, in mentis tranquillitate. Quotusquisque vero haec praecepta, has leges vivendi custodit? Homo frugi est rara avis, &c. Hinc nemo mortalium fere est sine catarrhis.9

Mr. Boulton will soon present you with one of the boxes with invisible Hinges. He has astonished our rural philosophers exceedingly by calming the waves a la Franklin.1

I am trying some experiments in relation to the improvement of telescopes. Should they answer you shall hear of them.

I beg you will make my most respectful Compliments to the fellow travellers who were with you here,2 and believe me to be with the highest regard Dear Sir Your much obliged and most obedient Servant