564 Transactions of the American Tnstftute. 



also very costly ; it has to be carried first by mules from the mine to 

 the road, where it is taken up in small carts to the nearest port, often 

 more than forty miles distant from the point of departure. 



Sicily and the south of Italy furnish nearly all the sulphur that is 

 employed in the arts and agriculture. In central Italy, near Bologna, 

 there is a vein of sulphur ore about fifteen miles long, but the mineral 

 is not rich, and it is necessarily taken from a great depth, sometimes 

 over 800 feet About 12,000 tons are produced here annually, which 

 is almost entirely consumed in the neighboring country for diseases 

 of the vine. The Papal States also produce sulphur, but the quantity 

 is small, not exceeding 500 tons. Sulphur has also been found in 

 small quantities in Gallicia, near Cracovy, Oorinthia in Hungary, in 

 the Grecian island of Milo, in Tripoli, isthmus of Suez, on the borders 

 of the Red Sea, province of Rio Grande in the north of Brazil ; but, 

 as already stated, it is from Sicily that we obtain the great bulk of 

 sulphur used in the arts. In this island the strata of sulphur extends 

 over a length of about 170 miles, superimposed one on the other to a 

 depth of from three to twenty-five feet, and containing about thirty 

 per cent of sulphur. 



Dr. P. H. Yan der Weyde — When I was in New Orleans, a year ago 

 last winter, I saw some of that sulphur. To my mind it is very doubt- 

 ful if it will pay. We must take into account that it is found 400 feet 

 under water. We may bore for oil, or for petroleum, or for salt that 

 can be brought up in solution, but I do not believe that that sulphur 

 can be got out at a price to compete with the Italian sulphur. For 

 sulphuric acid, iron pyrites are used now instead of sulphur. 



The President — The point suggested is very important. Two years 

 ago we had specimens of lignite presented from New Jersey, not 

 more than thirty-five miles from this city ; but it turned out that it 

 was under a bed of sand, and that it would cost more to dig it out and 

 brace up the sand with timber than the lignite was worth. In mining 

 coal, where the roof is of rock, there is not this difficulty. 



Dr. Van der Weyde — In mining there are thousands of instances 

 of this kind. In Philadelphia, there is gold in all the clay and all 

 their bricks ; but it will not pay to take it out. So there are millions 

 of dollars worth of silver in sea-water, but it will not pay to take it 

 out. 



II. Impeoved Miceoscope. 



Dr. Royston Pigott has made a series of investigations which seem 

 to show that objectives of high power sometimes give distorted 

 appearances, and he has been led to employ lower powers which give 



