Some of the select committees are appointed regularly every year, and are therefore known as sessional committees. One of these, the Committee of Selection, has already been mentioned. It has been enlarged from time to time, and now consists of eleven members, chosen by the House itself at the beginning of the session.[266:1] The members are, in fact, designated by an understanding between the leaders of the two great parties in the House. But the object is to create an impartial body, and so far is this object attained that in the memoir of Sir John Mowbray, who was its chairman continuously for thirty-two years, we are told that divisions in the committee are rare, and never on party lines.[266:2] Its duties, so far as public business is concerned, consist in appointing members of select and standing committees. It appoints also the committees on all private and local bills, and divides those bills among them.[266:3] This is, indeed, the primary object of its existence, but, together with a description of the various committees employed in private bill legislation, it must be postponed to a later chapter. It may, however, save confusion in the mind of a reader unfamiliar with parliamentary practice to insist here upon the distinction between a private member's bill and a private bill. The former is a bill of a public nature introduced by a private member, whereas a private bill is one dealing only with a matter of private, personal, or local interest. [Sidenote: Other Sessional Committees.] The remaining sessional committees are the Committee on Public Accounts,[266:4] which goes through the report of the Auditor and Comptroller General, considers in detail objections to the legality of any expenditures by the public departments, examines witnesses thereon, and reports to the House; the Committee on Public Petitions, appointed to inspect the numerous petitions presented to the House;[266:5] and the Committee on the Kitchen and Refreshment Rooms, which has importance for the members of the House, though not for the general public.[267:1] [Sidenote: Other Select Committees.] [Sidenote: Their Object.]