At the auction the number of oysters to be sold that evening is announced, and bids are invited. Some one starts the bidding at, maybe, Rs.20 or 25, and this is advanced by successive bids until the limit appears to be reached, which may possibly be Rs.50 or 60. The successful bidder is permitted to take as many oysters in multiples of 1000 as he chooses; and after he is supplied, other merchants desiring them at that particular price are accommodated. If there is no further demand for them at that price, the bidding on the remaining oysters is begun precisely as at first, and when the maximum bid is reached, all merchants willing to give that amount are furnished with as many as they wish in multiples of 1000 as before. If this does not exhaust the oysters, the bidding on the remainder is started up again, and so on until all are sold.[153] No one knows at the time whether he is buying a fortune in gems or only worthless shells. [Illustration: Indian pearl merchants ready for business ] [Illustration: Children of Persian pearl dealers ] The prices at which the oysters are sold at auction may differ greatly from the estimated valuation of the samples secured in the February examination. For instance, in 1905 the valuation of the South Madaragam oysters was Rs.17.86 per 1000, yet the auction sales on the first day began at Rs.53 and went up to Rs.61 per 1000, or three times the valuation; and about the same general proportion of increase prevailed for the oysters from the remaining banks, a result of great advances in the market for pearls. The auction prices for the different lots and from day to day are fairly constant. But the shrewd Indian merchants know their business well and keep in close touch with the yield, so that there are many variations in the selling price that are puzzling to the uninitiated. A somewhat higher estimation is placed on the oysters from certain banks, and also on those from rocky portions of a particular reef, owing to their reputation for yielding a larger percentage of pearls. The estimation of particular oysters varies to some extent according to the amount of adhering rock and coral growth. As already shown, the prices in 1906 covered the remarkable range of from Rs.20 to 309 per 1000. Superstitious belief in luck also has its influence, and a buyer may consider a certain day as unfavorable for him and abstain from bidding on that occasion; or considering a particular day as lucky, he may bid very high to secure a considerable portion of the sales.