BALTIMORE COUNTY. 629

ers of Baltimore County at a private sale upon the best terms that can
be obtained for the same; provided they shall not be sold at private sale
for less than par and accrued interest. All payments of the purchase
price of said bonds shall be made to the County Treasurer. Such bonds
shall be designated "Baltimore County Metropolitan District Bonds,"
and shall be of such denomination or denominations and of such type,
either serial bonds, sinking fund bonds, or certificates of indebtedness of
other evidences of indebtedness, and of such periods of maturity, not
exceeding fifty years, and rates of interest, not exceeding 5 per cent, per
annum, as the Commissioners may deem advisable, said bonds to be signed
by the President of the County Commissioners of Baltimore County and
the Treasurer of said County and to have the corporate seal of Baltimore
County affixed thereto. Said bonds and the interest payable thereon shall
be and remain exempt from State, county and municipal taxation. At
no time shall the total issue of bonds outstanding for any purpose, under
this Act, exceed seven per centum of the total assessable basis of real and
tangible personal property assessed for county taxation purposes, within
the Metropolitan District. The payment of interest on, and the retire-
ment of, said bonds shall be provided for in the following manner: At
least thirty days before the regular annual levy day the Commissioners
in each year shall estimate the amount necessary to pay the interest on
all outstanding bonds for the ensuing year, plus such amount as may be
necessary to retire all such bonds maturing during the year for which
the taxes are levied, or to provide a sinking fund sufficient to retire all
such bonds as they mature, and shall levy annually against all taxable
property in the water, sewerage or drainage sub-district as hereinbefore
provided for such amount, less funds in hand, applicable to the payment
of interest and retirement expenses, for all the bonds issued to defray the
cost of the water, sewerage or drainage sub-district so improved or bene-
fited, provided that in the event such sum so levied on the water, sewerage
or drainage sub-district shall not provide a sufficient sinking fund to retire
all such bonds as they mature, then the Commissioners shall levy annu-
ally against all taxable property in Baltimore County a sufficient sum to
make up the deficiency. The Treasurer of Baltimore County is hereby
required to collect the tax so levied, in the same manner as State and
county taxes are collected, and such tax shall bear the same interest and
be subject to the same penalties in the event of non-payment, as in the
case of other county taxes. From the money so received, together with
the amount in hand to the credit of said bond fund from the collections
provided for in Section 335, the Commissioners shall first pay all interest
on said bonds as it matures, and shall then deposit in some bank, or banks
in Baltimore County to the credit of the Commissioners, as a fund to
be known as the "Sinking Fund Account," the amount so raised for the
payment of the principal of said bonds. The moneys in the Sinking Fund
shall be kept entirely separate from all other moneys of the said Com-
missioners and of the county, and the said Commissioners shall invest the
moneys in the Sinking Fund in the purchase of any bonds issued under