83. As to the Benefit of Ventilators in preserving the _Health and Lives_ of People in Slave and other Transport Ships, I have received farther Confirmation of their great Benefit, in a Letter from Dr. _Demainbray_, who has shewn Courses of Experimental Philosophy to his Royal Highness the _Prince_ of _Wales_ and _Prince Edward_, viz. “That in the Year 1753 Ventilators were put into the Vessels in the Slave Trade at _Bordeaux_, and in other Ports of _France_; the happy Effect of which was, that instead of the Loss of one-fourth of those valuable Cargoes, in long Passages from _Africa_ to the _French_ Plantations, the Loss seldom exceeded a twentieth. And since my Return to _England_, I have been informed of a _French_ Vessel, which by this self-evidently reasonable Precaution, saved 308 out of 312 Slaves, spite of most tedious Calms and a long Passage.” And Dr. _Garden_, in his Letter to me, dated _Charles-Town, South-Carolina, March_ 24th, 1756, says, _viz._ “It is indeed very wonderful, that the Slave Merchants do not come into the Use of Ventilators. There are few Ships come here from _Africa_, (even though they call for fresh Provisions and Water at the _Islands_) but have had many of their Cargoe thrown overboard; some one-fourth, some one-third, some lose half; and I have seen some that have lost two-thirds of their Slaves. I have often gone to visit these Vessels on their first Arrival, in order to make a Report of their State of Health to the Governor and Council; but I never yet was on board one, that did not smell most offensive and noisome. What from Filth, putrid Air, putrid Dysenteries (which is their common Disorder) it is a wonder any escape with Life.”