85. As to the curing the ill Taste of Milk from the Food of Cows; and also curing musty Liquors, I made the following Trials, viz. When in the Beginning of March the Turnips had made large Shoots, and were thereby become very rancid, two Cows being fed with Turnips only for seven Days, their Milk had a very disagreeable Smell and Taste. On ventilating it scalding hot, with ascending Showers of Air, at first the ill Smell increased, but in two Minutes that Smell was much abated; and with five Minutes Ventilation, there was only the common Smell of good Milk; which shows that the rancid Oil of Turnips, which gives the ill Taste, is very volatile: After ten Minutes Ventilation, there was no ill Taste or Smell; and it was the same after 15 and 30 Minutes Ventilation. By this means therefore the ill Taste of Milk from some Food of Cows, may easily be cured. Experience will show what Degrees of Ventilation will be requisite for larger Quantities of Milk; as also for curing the ill Tastes from different Kinds of Food; as also from the shorter and longer Times of feeding on such Foods. It is observable that the Breath of these Cows was disagreeable; whence we see how freely contagious Infections may be conveyed through the Lungs, from tainted putrescent Blood.
86. A Cow having been fed for sixty Hours with a good Quantity of Crow Garlick, mixed with cut Grass, towards the end of June, the Milk had a very disagreeable Smell and Taste; which was not cured, though something better, after 30 Minutes Ventilation, while scalding hot. I repeated the same Ventilations for 15 Minutes, with the two following Evening and Morning Milks of the same Cow, viz. 12 and 24 Hours after the Cow had left off eating Crow-Garlick; at which times the ill Taste and Smell was sensibly abated before Ventilation, and something more after it, yet was far from being cured. Hence we see that the ill Taste and Smell of the Crow-Garlick Milk, cannot thus be cured, tho’ somewhat amended. The ill Taste of this Cow’s Milk continued for about five Days after she had left off eating of the Crow-Garlick. And perhaps where Cows have eaten but a small Quantity of it, the Abatement of the ill Taste may be so considerable, as to recompence the Trouble of ventilating it. As Opportunities offer, I will make the like Trials, with other ill-tasted Milks, such as that from autumnal Leaves, &c. and hope that others will do the like.
87. Cream or Milk Sillabubs may most commodiously and easily be made in Plenty, in a few Minutes, by means of a small Tin Air-box, three Inches in diameter, and three quarters of an Inch deep; the flat Bottom of the Pot, which contains the Cream or Milk, to be but little wider than the Air-box, that the Air from the Box may the better come at it: But the wider and deeper the upper Part of the Pot is, so much the better, for the Froth expands much.
88. Scalding-hot musty Vinegar was cured by repeated Trials, of near three Gallons in each Trial, by ten Minutes Ventilation. And giving Vinegar a scalding Heat, does not weaken or damage it, as it does Wine, whose vinous Spirit is carried off both by Heat and Ventilation; for when some strong musty Raisin Wine was ventilated hot, it was cured in five Minutes: But the vinous Spirit, which strongly affected the Nose in flying off during Ventilation, being gone off, the vapid Wine would not kindle into a Blaze, when thrown into the Fire, as it did to a great Degree before it was heated and ventilated. Neither musty Wine nor Vinegar were cured, tho’ something bettered by 30 Minutes Ventilation, when cold.
89. Mr. Jones, a Chemist in Cranbourn-Ally, Leicester-Square, ventilated a Gallon of Proof Malt Spirits 15 Minutes cold, in which time it wasted two Ounces and half; whereas a like Quantity of common cold Water wasted but half an Ounce in 15 Minutes Ventilation, viz. but one-fifth part of what the Spirits did; and the same Spirits ventilated hot, wasted no less than 5 Ounces in 5 Minutes; which Ventilation made them sensibly better tasted than the unventilated. But the great Waste shows that these volatile vinous Spirits, ought not to be ventilated, neither hot nor cold. Besides that, the 15 Minutes cold Ventilation had but little Effect in bettering the Spirit.
90. In order to know whether Fish in a Vessel of Water would live the longer for having Showers of Air blown up thro’ the Water, May 25, 1756, at seven in the Morning, the Wind N. E. the Mercury in Farenheit’s Thermometer, 50 Degrees, and it continued so cold, that at one o’clock it rose but to 60 Degrees; I put twelve Dace into a Pail A in two Gallons of fresh Pond-Water, thro’ which a Stream ran, and twelve more into a Pail B, with the like Quantity of Water; one of which Fishes in B was sick, as appeared by turning its Belly upwards; as were also two Fishes in the Pail A, which was occasioned by being all brought in a Pail above half a Mile from the Thames.
91. At 45 Minutes past 8, most of the Fish in the Pail B, were turned Belly upwards, and lay as dead; at 30 Minutes past 9 seven of them were dead; at 30 Minutes past 11 all but three were dead; at two o’clock but two Fish remain alive in B; which remained alive, tho’ sick, at ten that Night, viz. at the end of 14 Hours.
92. The good Effect of blowing every quarter of an Hour, with 25 Strokes each time with double Bellows, Showers of fresh Air up thro’ the Water, was, viz. they all continued well, and the larger of the two sick Fish recovered; but the lesser died at 4 o’clock, viz. at the end of nine Hours; upon each Ventilation it turned its Back upwards; but soon after the Ventilations, it constantly fell precipitate with its Head foremost, to the Bottom, and there turned Belly upwards. After 4 o’clock the ventilated Water frothed with larger Bubbles, this owing to the Slime of the Fish. The last Ventilation was at 10 at Night, when the Fish in the ventilated Water were well, and would probably have long continued so by the Salutariness of Ventilation; but that being discontinued, they were all found dead the next Morning, except one which had some small Degree of Life.
93. June 7, the Wind S. W. cloudy, the Thermometer at 58 Degrees, 13 live Gudgeons were put into two Gallons of fresh Pond-water in a Pail A; and a like Number into a Pail B, at 10 Minutes before 7 in the Morning. At 50 Minutes past 7, two in B began to be sick; at 8, half of them came up for Air, and showed Uneasiness; at 15 Minutes past 8 two are dead; at 30 Minutes past 8, eight more turned Belly upwards; at 8 Minutes past 9, five are dead in B, and five more sick; at 30 Minutes past 9, seven are dead, and four sick, two well; and 30 Minutes past 10, eight are dead; at 11 two only alive, and also well, though they showed some Uneasiness by their raising their Mouth to the Surface, which they continued to do till nine, when they were taken out of the Water. Hence we see, by this, and the preceding Experiment on Dace, that one or two Fish may be kept alive many Hours longer than a greater Number can be, by means of the small Portion of fresh Air, that is continually mixing with the Water, on which it presses.
94. The Water in the Pail A was ventilated from 10 Minutes before 7, to 6 in the Evening, by blowing every quarter of an Hour Showers of fresh Air up thro’ it, with 25 Strokes of the Bellows; by which means the Fish continued all well, laying quiet at the Bottom: At six we ceased to ventilate; for an Hour and half after which, there was no Signs of Sickness, after two Hours two of them showed Signs of Uneasiness; and at nine most of the Fishes turned Belly upwards, and lay at the Bottom dead or dying. By comparing this Event with that at eight in the Morning, we see there is more Air in this ventilated Water than in the Pond-water, as is probable by the Gudgeons living longer in it without Ventilation, than in the Pond-water. And accordingly the specific Gravity of unventilated Pump Well-water, was a very small Matter greater, than that of the same, after being ventilated with 100 Strokes of the Bellows, as I found by the Hydrometer; and there was nearly the same Difference between the specific Gravity of unventilated and ventilated Table Beer.