One hundred and fifty tons of West Castle ton slate have been carried to Boston within the past week, making 350 tons in two weeks, over the. Rutland, Cheshire, and Fitchburg roads. A gang of 500 men are to be employed in getting out this slate the com ing summer. Extensive machinery is also to be introduced, and with these increased facili ties, the directors of the company are confi dent that they can supply the American mar ket with American slate of a superior quality, and at a much cheaper rate than has. hereto fore been paid.