VOL. XXVI.J PHILOSOPHICAL TRANSACTIONS. 483 



very minute interspersed vacuities ; but not like those cavities which are very 

 observable in the freezing of common water. But at the bottom of the other 

 glass, they appeared in great numbers, of a longish form, seemingly pointing 

 all round from the circumference to the centre ; and there were none of those 

 salt-like figures on the sides of this, as on the other, but it was almost clear 

 from any adherence of ice, excepting towards the upper part near the neck, 

 where a little had fastened itself with those longish bubbles, pointing from that 

 part downwards, inclining to the pentre. From all which I conclude, that the 

 ice produced from the water purged of air, was equally augmented in its bulk to 

 the quantity of water from which it was produced, as that which proceeded 

 from the frozen common water ; for had the glasses been of an equal content, 

 I see no reason to doubt, but the water would have been equally frozen in both, 

 and the ascent of the unfrozen part of them would have been much the same 

 in their tubes. But if there be any difference, the water purged of air seems 

 to claim the easier disposition to be frozen. 



The water I freed from air in the following manner, viz. I first boiled it well 

 over the fire ; afterwards I included it in vacuo, where it remained in that state 

 till it was cold ; from whence I took it, and proceeded presently on the experi- 

 ment, which on two trials succeeded alike. 



An Experiment of the Freezing of Common Water, tinged with a Liquor said to 

 be extracted from Shell-Lac. By Mr. Francis Hauksbee. F. R. S. N° 320, 

 p. 304. 



This liquor is a very deep red ; and a small quantity of it will tinge 20 times 

 as much of common water of a very good sanguine colour, hardly transparent. 

 I found that this liquor, extracted from lac, would not freeze ; for during the 

 coldest weather we have lately had, it retained its fluidity ; and when it was 

 mixed with water, and exposed to freeze, the water, in which it was mixed, 

 soon congealed ; and so much of it as underwent the change, appeared of a 

 fine but pale transparent red; the body of the colour retiring into the middle, 

 in form of aa, fig. 2, pi. 12, and was quite opaque. And when no more of the 

 mixed liquor would fi*eeze, I took the body of ice out of the glass, by just 

 warming its sides by a fire; and pricking the dark part of it with a piece of wire, 

 the red liquor immediately issued out through the hole I had made, seemingly 

 as pure and as abstracted from any mixture of water, ,as it was before it was put 

 into it. This red liquor I found to be somewhat specifically heavier than com- 

 mon water. Another thing very remarkable, was, that this retired liquid, as it 

 seemed to keep at an equal distance from the sides of the glass, so also did it 

 from the bottom and top ; which upon repeated trials answered alike. 



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