T 0817/90 (Hair waving/CHESEBROUGH-POND'S) 12-11-1993

1. The appeal is admissible.

2. Formal allowability of the amended claims (Art. 123(2) EPC)

There are no objections under Article 123(2) EPC to the amended application documents as the corrections which have been introduced therein under Rule 88 EPC (see item 3 below) do not result in an extension of the application beyond its original content.

3. Correction of errors (Rule 88 EPC)

The Board considers that the proposal by the Appellant to change the expression of the unit of conductivity from "micromhos" to "micromhos per centimetre" in the application amounts to a request for a correction under Rule 88 EPC. In fact, it is self-evident that, from a formal point of view, the "conductivity" of a solution is only correctly expressed when the unit of distance is indicated. The unit of distance was omitted in the original application documents.

According to decision G 11/91 of the Enlarged Board of Appeal (OJ EPO 1993, 125), which is concerned with question of the correction of errors, "the skilled person must thus be in a position objectively and unambiguously to recognise the incorrect information using common general knowledge". The said decision states also that "evidence of what was common general knowledge on the date of filing may be furnished in connection with an admissible request for correction in any suitable form".

Therefore, the question at issue in the present case is whether such correction can be allowed under the provisions of Rule 88 EPC. According to this Rule, second sentence, "the correction must be obvious in the sense that it is immediately evident that nothing else would have been intended than what is offered as the correction".

3.1. The terms "conductance" and "conductivity" are used, when referring to electrolytic solutions, as an indicator of their property of transmitting an electric current.

The SI unit of "conductance" is the Siemens (S) which is the equivalent of ohm-1 or mho in the CGS system.

"Conductivity" is commonly expressed in the art either in terms of Siemens/m or in terms of Siemens/cm (see, for example, "Quantities, Units and Symbols in Physical Chemistry", IUPAC, 1988, prepared by I.Mills et al., Blackwell Scientific Publications, Oxford, pages 66-67; "A New Dictionary of Physics", H.J.Gray and A.Isaacs eds., 1975, Longman, pages 107-108; "Römpps Chemie- Lexikon" O-A. Neumüller, 8th Edition, 1981, Franckh'sche Verlagshandlung, Stuttgart, page 1085). However, the conductivity of electrolyte solutions is usually expressed in terms of Siemens/cm (ohms-1/cm) or, in the American and British usage, but not exclusively, in terms of mhos/cm (see "Hackh's Chemical Dictionary", loc.cit., and "Dictionnaire de la Chimie et de ses Applications", 3rd Edition, C.Duval and R.Duval, 1978, Technique et Documentation, Paris, pages 283, 704 and 771). Standard conductivity meters are, in fact, constructed and calibrated so as to provide readings in ohm-1/cm or mhos/cm.

As pointed out by the Appellant, in the American/British usage scientists commonly report conductivity measurements in "mhos" and omit the unit of distance (see, for example, the "Operating Instructions for Model 1052 digital conductivity meter", MARKSON submitted by the Appellant as enclosure to the letter dated 10 January 1990). This practice of scientists of using "abbreviations" is in fact at the origin of the imprecise terminology used in the present case.

At any rate it is observed that the conductivity values reported in the present application are compatible with "standard" measurements. Thus, in spite of the fact that no indications are given with respect to the instrument which has been used, it is plausible that a "standard" conductivity meter was used wherein the electrodes were 1 cm apart.

In the Board's opinion, the requirements quoted above (see item 3) for admitting a correction under Rule 88 EPC are fully met in the present case. In fact, the skilled person, who is normally aware of the different ways of expressing units of measurement, when reading the original application documents, would immediately recognise the incorrect terminology used therein. He/she would, therefore, read the expression "micromhos" in connection with the reported conductivity values as meaning implicitly "micromhos per centimetre" and nothing else.

Therefore, the change in the application documents from "micromhos" to "micromhos/cm" is regarded as an allowable correction under Rule 88 EPC.

4. Rule 35(12) EPC

Rule 35(12) EPC requires inter alia the use of units recognised in international practice in the expression of physical values. Since, as already stated above, the expression of conductivity in terms of "mhos/cm" is recognised in international practice, the Appellant, in line with the suggestion by the Board, has chosen to express the conductivity in terms of the SI unit "Siemens" (S) (here: µS) and to proceed as suggested also in the Guidelines for Examination, Part C, Chapter II, 4.15 by putting in parenthesis the expression "micromhos/cm".

For the same reasons the temperature value on page 7, line 28 of the description has been expressed also in degrees Celsius.

There are no objections to said amendments.

5. For the above reasons, the amended application documents are considered to be formally acceptable under the quoted provisions of the EPC.