('2040 ) 
written to the Publlfher^ by the faid Dof^ot Bartkolm from 
CopefjhagenVthY^7j. 16705 Engliih't as foliolte 3 
I Know the many Excellencies of the Eng!i(h Na- 
tioHj and that innumerable new things in the matter of 
knowledge iffiie thence , and difTufe themfelves through Eu- 
rope 3 though they arrive fomewhat Oowly hither. We are 
here prefled with io many cares, that though we want no will 
to contribute fomething to the advancement of knowledge 3 
yet being de ftitute of the leifure necelfary for it, and diver- 
ted by two difficultProfeffionSj the xMedica! and Mathemati- 
calj we can rather admire the performances of others^ than 
engage for any thing of our own. But yet, not altogether to 
fruftrate your expeciation^ and to give you fome Teftimony 
of my affeflionand endeavors, I here lend you (bme Experi- 
ments made with a certain Chryftal-like Stone, fent meoutof 
y/?4»^3together with a piece of that Stone^ to make the Tryals 
your felf. Farewell. 
For the reft, we are now labouring to publifli a more cor - 
redied and better digefted Edition of Tycho Brakes Works 5 
a bufinefs of much time and exceeding great labour : Which 
care while I arn engaged in, I muft lay afide other matters. Yet 
Ihope^that my part in this work will (hortly be over 5 there 
remaining almoft nothing, but to provide the charges neceP- 
fary for thelmpreffion^ v/hich all true Lovers of Aftronomy 
cannot but have a great coRcern for. 
This Letter being fent to HaMbarongh to that Ingenious 
Pbyfitian, Dr» Matthias Paififtiw, with a defire to tranfinit 
k to London^ this worthy Perfon was pleafed to inclofe it in 
one of his.written to the Publifher 3 which, fince it trcateth 
of the lame argument {Im^zUythQ lJlandian Stone,^ will not 
be amifi to fubjoyn here the Breviate of. 
■ " lh$ Obfer vat ions of the Ex^e//e»^ Bartholin upon the 
Ifland-Chryftal are indeed confiderable as well as fainfulL 
We have here alfo made fome Tryals of it upon a piece Jse prefented 
me with 5 vphich confirm his obfervations, Mean timejpoe found 
it.fo'f^mhatfcijfUe and rednaible by a k^ife into thin lamina s 
