ngers and freight, a
statute which taxed the capital stock of all corporations doing business
within the State. Such transactions, the Court held, were interstate
commerce; nor were the company's vessels subject to taxation by
Pennsylvania, their taxing _situs_ being in the company's home State.
The only property held by the company in Pennsylvania was the lease
there of a wharf which could be taxed by the State according to its
appraised value; and the State could also levy reasonable charges by way
of tolls for the use of such facilities as it might itself furnish for
the carrying on of commerce. This ruling rested on two earlier ones. In
1855, the Court had held that vessels registered in New York, owned by a
New York corporation, and plying between New York City and San Francisco
had the former city for their home port, and were not taxable by
California where they remained no longer than necessary to discharge
passengers and freight;[726] and in 1877 it had sustained Keokuk, Iowa
in charging tolls for the use by vessels plying the Mississippi of
wharves owned by the municipality, said tolls being reasonable and not
discriminatory as between interstate and intrastate commerce.[727] Today
it is still the general rule as to vessels plying between ports of
different States and engaged in the coastwise trade, that the domicile
of the owner is deemed to be the _situs_ of the vessel for purposes of
taxation,[728] unless the vessel has acquired actual _situs_ in another
State, by continuous employment there, in which event it may be taxed
there.[729] Recently, however, this long standing rule has been amended
by the addition to it of the apportionment rule as developed in the
Pullman case. This occurred in Ott _v._ Mississippi Barge Line Co.,[730]
decided in 1949, in which the Court sustained Louisiana in levying an
_ad valorem_ tax on vessels owned by an interstate carrier and used
within the State, the assessment for the tax being based on the ratio
between the number of miles of the carrier's lines within the State and
its total mileage.

Airplanes

When, however, it was confronted by an attempt on the part of the State
of Minnesota to impose a personal property tax on the entire air fleet
owned and operated by a company in interstate commerce although only a
part of it was in the State on tax day, the Court found itself unable to
recruit a majority for any of the above formulas.[731] Pointing to the
fact that the c