VOL. v.] PHILOSOPHICAL TRANSACTIONS. 441 



bottom, and is afterwards melted ; the aquafortis is distilled from the silver, 

 and serves again for use. 



The silver then separated from all its former associates, is sent to Chremnitz, 

 where they coin it into pieces of a mixed metal (which is the common money 

 of the country,) after this manner : They melt it with about the same quantity 

 of copper, and run it into bars, which they beat out : then softening them in 

 the fire, draw them out to an exact thinness between two steel wheels; then 

 they cut them out into round pieces with an instrument like a shoemaker's 

 punch, and then boil them with tartar and salt, shake them in a sack with 

 small-coal and water, dry them in a kettle perforated, and afterwards they are 

 drawn between two wheels, in which they receive their stamp. 



Some Inquiries relating particularly to the Bleeding of Walnuts ; sug- 

 gested by Dr. Ezerel Tonge, in a Letter to the Editor, March 22, 

 1670. iV' 58, _p. 1198. 

 In these inquiries there is nothing sufficiently interesting for an extract. 



Extract of a Letter from Francis JFilloughby, Esquire, to the Edi- 

 tor, containing some Ohseiuations of his made on some Sycamore 

 Trees, the Black Poplar, and the Jf^alnut : as also his Thoughts 

 about the Dwarf Oaks, and the Stellar Fish, described in N° 57 - 

 N'dS, p. 1199. 



I am sorry I cannot return you a better answer to yours of March 19 ; the 

 experiments which our leisure has since permitted us to make, being not suffi- 

 cient to found a new hypothesis on, to confirm Dr. Tonge's. Since the leaves 

 have been unfolded, we have observed the sycamore after several frosty nights 

 to bleed afresh in the morning, soon after sun-rising, when it had ceased 

 several days before: though this must not be understood of all sycamores, but 

 of some only that are more sensible and observ^ant of the weather. 



April 3 and 4, all the sycamores quite ceased. 



The 5th, being after a white frost, they began to bleed about eight o'clock, 

 and ceased towards noon. 



The Qth, 12th, 13th, 15th they bled again. 



The 10th, 11th, 14th were not observed. 



This 16th they bled not, it being rainy and the sun not shining. 



From the observations we have hitherto made, we think it may be certainly 

 inferred, that a morning-sun after a frost will make all the bleeding tribe bleed 

 afresh, though they had before ceased ; and that this new bleeding towards the 



VOL. I. 3 K 



