1.

With regard to the first question, reference should be made first of all to Note 1 (f) to Section XV (within which heading 73.21 also falls) in which it is stated: ‘This section does not cover: … (f) Articles falling within Section XVI (machinery, mechanical appliances and electrical goods)’. Since, according to Rule 1 of the Rules for the Interpretation of the Nomenclature, the Section Notes determine classification, the heading of Section XVI (‘Machinery and mechanical appliances; electrical equipment; parts thereof’) is important with regard to Section XV. The Commission has demonstrated, convincingly in my view, with reference to the relevant texts, that the mobility factor, a constant process of mechanical movement, is characteristic of machinery in its diverse forms and of mechanical appliances. The term ‘Apparat’ (device) is even wider and according to those observations covers all tools used for the conversion of energy. The significant feature of structures, which are referred to in tariff heading 73.21. is that they are stationary, that is to say that, in principle, they remain permanently at rest. This is in fact apparent from the examples given in heading 73.21 and is confirmed by the Explanatory Notes to the Brussels Nomenclature in relation to heading 73.21 which are of direct relevance for the interpretation of the Common Customs Tariff in view of the reference thereto in the Explanatory Notes. This is not altered by the fact that in the Explanatory Notes there is mention of ‘adjustable or telescopic props and similar equipment’. The said characteristic facilitates simply the bringing into position; when in position, however, support structures remain stationary. The mobility achieved does not influence the nature of support structures as ‘equipment’, and in this connexion it should not be overlooked that Chapter 73 is a ‘materials’ chapter, which distinguishes articles mainly on the basis of the materials of which they are composed. Against the background of these basic facts it is important to note in the present case that the appliance to which the contested notification relates is an article which, as appears from the description, is characterized by the fact that it moves by mechanical means. It is equipped with a special arrangement of hydraulic components, resulting in an interplay of hydraulic forces. The individual hydraulic processes complement each other; as a result, all parts of the machinery are designed to allow for movement. Since the appliance accompanies the mining work under its own power it cannot be said that it is intended to remain stationary. Moreover, its permanent mobility enables the independent carriage of winning machines, to which, clearly, it is usually attached. Even if movement on each occasion lasts only a short while, as the plaintiff emphasized at the hearing, the fact that it is capable of movement must nevertheless be regarded as characteristic. It can accordingly not be said that, as is usual with structures, the stationary factors dominate, and seen in this light more is to be said for classifying the article under Chapter 84 rather than under heading 73.21. The Tariff Decision of 9 June 1972, according to which hydraulically extendable pit-props fall under tariff heading 73.21, is not decisive. The Commission has rightly pointed out that that classification was based on the preponderance given to the material of which they are made, whereas their mechanical nature was obviously of secondary importance. In the same way it is irrelevant that in the said Explanatory Notes to the Brussels Nomenclature relating to tariff heading 73.21 in connexion with adjustable or telescopic pit-props there is mention of ‘similar equipment.’ Since, as has been shown, the stationary factor is characteristic of tariff heading 73.21 similarity is a question of such properties and in this connexion the hydraulic factors are not a criterion. Reference to moving bridges which fall under heading 73.21 is also certainly unconvincing. The criterion for their classification is that the stationary structural elements preponderate, mobility not being the dominant feature. Finally, it should also be obvious that in this context no account can be taken of the provisions of patent law. The Commission has rightly observed that patent law and customs law are different areas of law, the rules of each having their own objectives, and that it is therefore not appropriate to draw inferences from classifications under patent law in relation to questions of tariff classification. If, as appears appropriate for the classification of borderline cases, the criterion is taken to be the dominant characteristics, then in view of all this the first question can be answered only to. the effect that the article with which we are concerned here does not come under the concept ‘structure’ within the meaning of tariff heading 73.21 because its characteristic feature is not the stationary element but its mobility.