At the public hearing of the Charles River Dam Commission yesterday morning, those in favor of the dam were given their first opportunity to state their arguments.

President Eliot was the first speaker. He said that the objections to the dam had come from small groups of persons representing comparatively insignificant interests. The principle reason for erecting the dam is to promote the health and happiness of the 400,000 people who live within easy walking distance of the seven mile park that would probably follow its erection. Furthermore, the construction of the dam is necessary to the proper sanitation of the valley below Watertown, because great areas of the river bottom are often left exposed at low water.

Major Henry L. Higginson said that an opportunity for making a beautiful water-park should not be missed, and that such a park as would be laid out is needed to give the public at large better opportunity for outdoor recreation.

Representatives of the North and South Ends spoke of the great need of the young people in those sections for better bathing and skating facilities such as would be afforded by the proposed water-park. The editor of a leading Italian newspaper in Boston spoke for the Italian residents of the district, saying that these people were very fond of open air life and would keenly enjoy the privileges of a new pleasure ground.

Dr. John S. Blake said that he thought he represented the sentiment of the medical men of the Back Bay in insisting that something ought to be done to improve the health conditions of the basin, and that the dam is the best means of accomplishing this purpose. Mr. J. M. McClintock, an engineer, showed the value of the dam in improving the present bad condition of the the sewage system.

Mr. J. J. Storrow summed up the arguments for the dam, and after emphasizing its value in furnishing a park and promoting health, said that it would cost the city practically nothing. For though the expense of building the dam, be said, would be $1,200,000, this is but half the sum which has been expended on the new Cambridge bridge. If a dam bearing a roadway could have been built in place of this bridge, the city would have not only secured the dam, but would also have saved about $1,000,000. A dam with a roadway could be built with equally favorable results in place of the Craigie bridge, and furthermore, the building of a dam would avoid the expenditure, otherwise necessary, of $400,000 for dredging the basin.