The Van der Hoop gallery is in the Academy, and was a bequest from the proprietor. The Academy hesitated long before accepting the valuable present, the institution then lacking funds to pay the high legacy-duty.
I was much interested during my visit to the diamond-cutting works of Herr Costa, reputed to be the chief establishment of the kind in existence. The Dutch enjoy an acknowledged pre-eminence over all the nations of Europe in the art of cutting diamonds; but in India they have found their masters, as is proved by the great diamond in the possession of the sultan, which was cut in Upper India. This diamond, the largest known to exist, though convex on the under side, has been cut in facets of uniform size, with an amount of skill which even the Hollanders are unable to emulate.
The size of the manufactory is very striking when one considers the smallness of the objects manipulated; the building is more than a hundred feet long and three stories high.
The various operations are conducted in the following way: the rough diamond passes first into the hands of the planer, then into those of the cutter, and finally is handed to the grinder. The first of these operators removes any defects that may be in the stone with a sharp diamond, wherewith he files the gem, and then chips off the faulty piece. The cutter gives the stone its proper shape by getting rid of the corners and inequalities in the same way. The dust obtained by these operations is carefully collected and husbanded, for the use of it is indispensable in grinding the diamond. The grinder uses a leaden bullet inclosed in wood, with the upper portion softened in the fire, so that the stone may be pressed into it as far as necessary. The diamond is then ground on a steel plate, on which a little diamond-dust has been strewn. The great art consists in making the facets and corners perfectly even, whereby the fire and beauty of the diamond are greatly increased.
The turning of the grinding machine (by steam power) is so rapid that the steel disk does not seem to move at all; it makes two thousand revolutions per minute.
A great deal is lost by this grinding; thus the English crown diamond Kôh-i-Noor was reduced one fourth in size on being cut the second time. The first cutting of this beautiful diamond had proved a failure, and in 1852 the English government sent for a Dutch workman from Herr Costa’s establishment to cut the stone artistically. The work occupied the lapidary for six months, and the mere working expenses, apart from any profit, which indeed the proprietor of the factory, Herr Costa, would not accept, amounted to four thousand Dutch guilders, or something more than £330 sterling. In Herr Costa’s works, of which he is sole owner, 125 workmen are employed, of whom five are planers, thirty cutters, and ninety grinders. These men earn each from thirty to seventy and eighty Dutch guilders per week.
In Amsterdam I saw also the sugar-refining works of Messrs. Spakler, Neoten, and Fetterode. The sugar is refined by means of steam-engines. I have seen the same thing done in other countries. This manufactory turns out about 5,000,000 kilos (about 4885 tons, English weight) of sugar every year. The greatest establishment of the kind in Holland manufactures 16,000,000 kilos, and the entire produce amounts to 80,000,000.
Very near Amsterdam lies the famous Haarlem Lake, the draining of which may be certainly reckoned among the most gigantic undertakings of the present century. Where a few years ago great ships sailed, and where the fisherman spread his nets, thousands of cows now graze, and beauteous fields and meadows smile with verdure; nay, scattered houses, already fast increasing, will soon probably expand into towns and villages.
The pumping out of this lake, which was about thirteen feet deep, was begun in February, 1849, and the whole great work was completed in four years. Engines of 400-horse power were set up in three different places; each of these engines raised the pistons of eight pumps six times a minute, and poured out the water into the canals leading to the sea. The twenty-four pumps of the three engines discharged 20,340 kilderkins of water per minute.
The area of land thus gained amounts to no less than 60,000 English acres. The cultivation of this great tract was begun as early as 1853.