facto_ unconstitutional. The leading case is Welton _v._ Missouri,[569] decided in 1876, in which a peddler's license tax confined to the sale of goods manufactured outside the State was set aside. The doctrine of Welton _v._ Missouri has been reiterated many times.[570] STOPPAGE IN TRANSIT It also follows logically from Coe _v._ Errol,[571] and the cases deriving from it, that a State may impose a nondiscriminatory tax when there is a break in interstate transit, and the goods have not been restored to the current of interstate commerce. The effect of an interruption upon the continuity of an interstate movement depends upon its causes and purposes. If the delay is due to the necessities of the journey, as in the Coe case, where the logs were detained for a time within the State by low water, they are deemed "in the course of commercial transportation, and * * * clearly under the protection of the Constitution."[572] Intention thus often enters into the determination of the question whether goods from another State have come to rest sufficiently to subject them to the local taxing power. In a typical case the Court held that oil shipped from Pennsylvania and held in tanks in Memphis, Tennessee for separation, distribution and reshipment, was subject to the taxing power of the latter State.[573] The delay in transportation resulting from these proceedings on the part of the owners, the Court pointed out, was clearly designed for their own profit and convenience and was not a necessary incident to the method of transportation adopted, as had been the delay of the logs coming from Maine in Coe _v._ Errol. The distinction is fundamental.[574] Applying this rule in more recent cases, the Court has upheld State taxation: on the use and storage of gasoline brought into the State by a railroad company and unloaded and stored there, to be used for its interstate trains;[575] on gasoline imported and stored by an airplane company and withdrawn to fill airplanes that use it in their interstate travel;[576] on supplies brought into the State by an interstate railroad company to be used in replacements, repairs and extensions, and installed immediately upon arrival in the taxing State;[577] on equipment brought into the State by a telephone and telegraph company for operation, maintenance, and repair of its interstate system.[578] In all these cases the Court applied the principle that "use and storage" are subject to local taxation when "there is an interval after the articles have reached the end of their interstate movement and before their consumption in interstate operation has begun."[579] On the other hand, in the absence of such an "interval," the Court declared invalid State gasoline taxes imposed per gallon of gasoline imported by interstate carriers as fuel for use in such vehicles, and used within the State as well as in their interstate travel.[580] THE DRUMMER CASES; ROBBINS _v._ SHELBY COUNTY TAXING DISTRICT