The general jurisdiction of county commissioners does not extend beyond the limits of their respective counties. The St. of 1869, e. 266, respecting Malden Bridge, is a special act, giving certain powers to the county commissioners of Middlesex county. Some of these duties are to be performed annually. But no part of the act purports to extend their jurisdiction into other counties, and it is not to be presumed, without a clear expression of intention, that the Legislature would make such an extension. On the contrary, the acts cited by the petitioners show that when other counties, or towns belonging to other counties, are to be charged with a part of the expense of supporting a bridge out of their own county, some other tribunal than" the commissioners of the county where the bridge is situated is authorized to make the assessment. Impartiality would seem to require this. Writ to issue.