Watson Laidlaw and Co v Pott Cassels and Williamson: HL 26 Jun 1911

A patent was obtained for ‘improvements in centrifugal machines.’ It dealt with a means of supporting while preventing the oscillation of the spindle to which the basket rotated is attached, and the means employed was, in typical form, a hollow India rubber cone suitably supported, into which fitted a counterpart cone formed upon the spindle. The angle of the cone was not stated, but after a narrative of what had been achieved by previous invention the specification affirmed ‘the present invention consists in the employment of a cone approaching much more nearly to a cylinder, and whose elements do not pass through the centre of oscillation of the spindle.’ Previous cones had been as flat as an angle of 53 degrees. It was admitted by the expert witnesses that the most appropriate angle was between 25 degrees and 55 degrees. The patent was challenged on the ground of ambiguity and insufficient description, inasmuch as it covered the whole field from 53 degrees to 1 degree.
Held, allowing the judgment of the Second Division, on an equality of their Lordships – the Lord Chancellor and Lord Atkinson being in favour of reversing, and Lords Kinnear and Shaw in favour of maintaining – that the patent was not invalid.
Lord Chancellor (Loreburn), Lord Kinnear, Lord Atkinson, and Lord Shaw
[1911] UKHL 782, 48 SLR 782, (1914) 31 RPC 104
Appeal fromWatson, Laidlaw, and Co, Ltd v Pott, Cassels, and Williamson SCS 5-Feb-1909
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Cited by:
CitedMorris-Garner and Another v One Step (Support) Ltd SC 18-Apr-2018
The Court was asked in what circumstances can damages for breach of contract be assessed by reference to the sum that the claimant could hypothetically have received in return for releasing the defendant from the obligation which he failed to . .

These lists may be incomplete.
Updated: 17 July 2021; Ref: scu.619207