WORLD’S FAIR NOTES. Rhode Island is to build an “Old Stone Mill” at Chicago as a part of its exhibit at the World’s Fair in ’93. It will be an exact copy and of similar size as that which has added so much to the general attractiveness and historical interest of Newport. The actual erection of the Exposition buildings began in June, 1891. Now all of them are being pushed rapidly towards completion. Already several are under roof. About 4000 workmen are employed. Work proceeds day and night. Half a million dollars has already been expended in grading Jackson park and dredging extensive waterways throughout it. Hundreds of thousands are yet to be spent for landscape gardening, fountains, statuary, pleasure boats, etc. A number of observation towers, from which excellent views of the buildings and grounds can be obtained, will be erected in different parts of the park.