70. As it is found by Experience, that the Milk and Butter of Cows, which drink stinking Water, has a very bad Taste, this plainly shows that the Water retains its putrid Quality when mixed with the Blood; whence it is much to be suspected, that the stinking Water which is drank in Ships, by retaining its putrid Quality, even when mixed with the Blood, may thereby promote that putrid Distemper the Scurvy, as well as some other Distempers. And much more does the putrid close Air in Ships, which is mixed with the Blood from the Lungs, promote putrid and other Disorders: By the same Means also, pestilential Infections are taken in: For as the salutary Properties of good Air, are conveyed to the Blood by the Lungs, so are also the malignant Qualities of bad Air. 71. Thus also the putrid Water in marshy aguish Countries, may be a Cause of Agues, as well as the putrid Air which they breathe; which, as well as the putrid Water, may probably carry some of its putrid Quality into the Blood thro’ the Lungs. This Method therefore of sweetening stinking Water, by blowing Showers of Air up thro’ the stinking Water of some aguish Places, may be beneficial. 72. Live Fish may well be carried several Miles, by blowing now and then fresh Air up thro’ the Water, without the Trouble of changing the Water; for this Ventilation will not only keep the Water sweet, but also enrich it with Air, which is necessary for the Life of Fishes; with which Air they supply their Blood, by breathing the Water, thin spread, between their Gills: But stinking Water will kill Fish. 73. I have found that much of the heating Oil may be got out of Tar-water, by blowing Showers of Air up thro’ it when scalding-hot, for 15 or 30 Minutes, the longer the better; the less volatile, and more salutary Acid remaining. [Illustration: _page 59_ _Fig. 1._ _Fig. 2._ _Fig. 3._ _T. Jefferys sculp_ ] AN APPENDIX TO THE Treatise _on distilling_ Sea-Water, _sweetning_ Milk, _&c. which gives a farther Account how to procure still greater Plenty of_ Fresh-water _at Sea, and to sweeten ill-tasted Milk, Stinking-water, and musty Liquors_, &c. _by blowing Showers of Air up thro’ them_. 74. Several considerable Improvements having been made on the Subjects of this little Book, since the Publication of it, I shall here give a short Account of them, hoping they may in several Respects be of Benefit to the World; especially the great Improvement in distilling Plenty of Fresh-water at Sea.