VOL. XM.J PHILOSOPHICAL TKANSACTIONS. 387 



These Saxon coins were, denarii, or pennies ; for Greaves, of the denarius, 

 p. 117, says, in Ethelred's time it was the 20th part of the silver ounce troy, 

 and bigger than three of our present pennies ; and our goldsmiths weigh by 

 this penny-weight or 24 grains. Five of the Saxon pennies made a shilling, 

 and therefore 48 of those shillings made a pound, and 240 pennies made a 

 pound ; which is the present proportion of our penny and pound, though the 

 intrinsic value be about three to one different. 



Sir Henry Spelman, in his Glossary, speaks of sterling and denarius to be 

 the same ; and he directs to the statute made an. 1302, 31 Edw. I. wherein the 

 penny is called sterling, and the weight of the sterling is 32 grains of dried 

 wheat ; and I have weighed 32 grains of wheat, and they are equal to 24 grains 

 troy-weight, which is our Saxon penny. And an. 1496, J 2 Hen. VII. cap. 5, 

 there is another statute, wherein the sterling is of the same weight. 



I am credibly informed, that some of Egbert's and Ethelbert's coins were 

 found amongst them : these I saw, were iEthelstan's, who began his reign 

 about the year g25. Edmund Etheling's his brother, (for I take the Edmund's 

 to be his), who began his reign 94O; Edred, another brother, who began 

 his reign 946. 



^n Estimate of the Quantity of F'apour raised out of the Sea by the TVarmth 

 of the Sun; derived from an Experiment shown before the Royal Society, at 

 one of their late meetings: by E. Halley. N° I89, p. 366. 



That the quantity of aqueous vapours contained in the medium of the air, is 

 ▼ery considerable, seems most evident from the great rains and snows which 

 are sometimes observed to fall, to that degree, that the water thus discharged 

 out of the interstices of the particles of air, is in weight a very sensible part of 

 the incumbent atmosphere : but in what proportion these vapours rise, which 

 are the sources not only of rains, but also of springs or fountains, as I design 

 to prove, has not, that I know of, been any where well examined, though it 

 teem to be one of the most necessary ingredients of a real and philosophical 

 meteorology ; and as such, to deserve the consideration of this honourable 

 society. I thought it might not be unacceptable, to attempt by experiment, to 

 determine the quantity of the evaporations of water, as far as they arise from 

 heat ; which, upon trial, succeeded as follows. 



We took a pan of water, about 4 inches deep, and 7-r5- inches diameter, in 

 which was placed a thermometer, and by means of a pan of coals, we brought 

 the water to the same degree of heat, which is observed to be that of the air 

 in our hottest summers ; the thermometer nicely showing it. This done, we 

 affixed the pan of water, with the thermometer in it, to one end of the beam 



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