Sir Joseph Hobson, who planned the tunnel under the St. Clair river at Port Huron, Mich., was a railroad builder in Canada and the United States till 1870. He built the international bridge at Buffalo, and was upon its completion made chief engineer of the Grand Trunk railroad. He is a Canadian by birth , and is about 55 years old. T. E. Hillman lives at Sarnia, Ont. , is 50 years old, and has credit for the actual construction of the tunnel.