Last autumn I received from Mr Maclachlan of Lower Green, Mitcham, some specimens of india-rubber tape which had been for several years wound, under considerable tension, helically round copper Wire. At ordinary temperatures, after being peeled off, the material shows no tendency to contract; but Mr Maclachlan found that in hot water it almost instantly resumes its original dimensions.

I have recently reproduced almost exactly the same results by stretching sheet india-rubber, slightly warmed, helically round glass tubes, and immersing it for a short time in a freezing mixture.