60 PHILOSOPHICAL TRANSACTIONS. [aNNO 1673. 



Whence comes the best black marble ? Whether porphyry differ in nothing 

 from marbles, but in hardness ? 



Query, the ways of making artificial marble ; and whether that with which 

 the Elector of Bavaria has adorned his whole palace at Munich, so as to look as 

 rich and beautiful as any palace in Italy, is made, as some afiirm, of such gypsmn 

 as composes the plaster of Paris, which being put over the fire and let boil till 

 it cease of itself, after being cooled is kept dry for use ; mixing painters colours 

 with it for tinging or colouring it according to pleasure, and using it as the 

 burnt gypsum is at Paris ? Beside several other inquiries concering stones, 

 quarries, coal, &c ; and then concludes, that it would be useful to retrieve the 

 art of hardening and tempering steel for cutting of porphyry, &c. ; which the 

 Egyptians were masters of, of old, and after them the Greeks and Romans : in- 

 somuch that the neat and curious hewing and carving of obelisks, colosses, 

 statues, pots, urns, as also porphyry and other hard marbles, is now the object 

 of admiration to the most skilful workmen, who know not which way to rough 

 hew stones of that untractable hardness. 



On the Advantage of Virginia for Ship building, by a Gentleman. N° 93, 



p. 6015. 



The country of Virginia abounds every where with large and tall oaks, of at 

 least 50 or 60 feet in height, of clear timber, without boughs or branchings ; 

 being very fit to make plank of any size, very tough, and excellently well 

 enduring the water. — With abundance of pines for masts, no country, that we 

 know in the world, is better stored than Virginia. Besides there is another sort 

 of wood, called cypress, which is far better than any pine for masts, it being of 

 as tough and springy a nature as yew-tree ; bending beyond credit ; when dry, 

 much lighter than fire, and so well lasting in wet and dry, that it seems rather 

 to polish than perish in the weather. — The same country affords great abund- 

 ance of old pine for making rosin, pitch and tar. — The conveniency of planting 

 hemp for cordage and sail-cloths in that country is so great, that England might 

 in a short time be supplied, without being beholden to other nations for it. — 

 To these particulars add the great abundance of iron-stone in Virginia, which 

 has already been tried and found very good ; the conveniency of wood and lime- 

 stone being a great inducement to the making of iron, which might be done at 

 a much less rate there than here. 



To make Vines groiv to advantage, all over the Roof of a House. By Mr. John 



Templer. N° 98, p. 6016. 



He lets vines ascend by one single stem to the eaves of his house, cutting off 



