838 ARTICLE 23.

No gas corporation or electrical corporation shall make or grant any
undue or unreasonable preference or advantage to any person, corporation
or locality, or to any particular description of service in any respect what-
soever, or subject any particular person, corporation or locality or any
particular description of service to any undue or unreasonable prejudice
or disadvantage in any respect whatsoever.

Nothing in this sub-title shall be taken to prohibit a gas or an electrical
corporation from establishing a sliding scale for the automatic adjustment
of charges for gas, electricity or any service rendered, or to be rendered,
and the dividends to be paid to stockholders of such gas corporations or
electrical corporation, provided that the sliding scale shall have been filed
with the proper commission; but nothing in this subdivision shall operate
to prevent the commission from fixing proper, just and reasonable rates
and charges to be made for service, as authorized in this article.

This section was passed to remove any statutory barrier to comprehensive effect
as to rate regulation of P. S. C. Law. Consolidated Public Utilities Company (of
Westminster) is within the operation of P. S. C. Law; pre-existing provisions of
charter of Westminster in conflict with the exclusive exercise of regulative power
by P. S. C. as to that company, repealed. Act of 1910, ch. 341, regulating rates of
the water company is in violation of that part of art. 3, sec. 33, of the Md. Con-
stitution which prohibits the passage of a special law for a case covered by an
existing general law. Westminster v. Consolidated Public Utilities Co., 132 Md. 378.
See notes to secs. 304, 346 and 362.

An. Code, sec. 445. 1910, ch. 180, sec. 31 3/4 (p. 376). 1914, ch. 445, sec. 31 3/4.

388. The Commission shall have the general supervision of all persons
and gas corporations and electrical corporations and other corporations
having authority under any general or special law, or under any charter or
franchise, to lay down, erect or maintain wires, pipes, conduits, ducts or
other fixtures in, over or under the streets, highways and public places of
any municipality, for the purpose of furnishing or distributing gas, both
natural and artificial, or of furnishing, or transmitting electricity for light,
heat or power, or maintaining underground conduits or ducts for electrical
conductors.

Investigate and ascertain, from time to time, the quality of gas supplied
by persons and corporations, examine the methods employed by such per-
sons and corporations, in manufacturing, selling, delivering or supplying
gas or electricity for light, heat or power, and in transmitting the same, and
have power to order such improvements as will best promote the public
interests, preserve the public health and protect those using such gas or
electricity and those employed in the manufacture and distribution thereof,
or in the maintenance and operation of the works, wires, poles, lines, con-
duits, ducts and systems in connection therewith.

Have power by order, to fix from time to time such reasonable standards
as it may deem proper for the measurement of the purity of gas, and of the
illuminating power of gas, and of the heating power of gas, for lighting,
heating, or power purposes, whether natural gas distributed or sold, or gas
manufactured, distributed, or sold by persons or gas corporations for such
lighting, heating, or power purposes, and to prescribe from time to time the
efficiency of the electric supply system, of the current supplied, and of the