A PROPOSITION has been made that arches should be placed under the two bridges nearest the boat-house, and the piles which now support them should be removed. The advantages of this plan are obvious. Should it be adopted, the ordinary scratch-race course would be much improved. As the races are, with the exception of single and double sculls, rowed now with coxswains, there would be no difficulty in having the boats shoot the bridges, one boat under the draw and the others under the proposed arches. The only disadvantage of the plan is the difficulty of carrying it into execution; and this, it must be confessed, is a serious drawback. If the change in the construction of these bridges should be made, it would be done at the expense of the city of Cambridge or of the State, according as one or the other has control of the bridges. Neither would have any advantage in making the change, and unless a very strong petition could be presented to the proper authorities it would be useless to attempt to induce them to do anything about it. Nevertheless, the construction of the arches would be of so much advantage to our boating interests that we hope an attempt, at least, will be made to induce the authorities to undertake the work.