Page 6 Advertisements Column 3

Otago Daily Times, Issue 18007, 6 August 1920, Page 6

Tho chirping of grasshoppers is caused by a thin, horny membrane stretched at tho rear of one wing-case, and! against the extremity of this case Ilio inscct rubs the finely-notched under-edge of the other wing-case. Black pearls were first mado fashionable by the- Empress Eugenie, who in tho days of her glory possessed a famous necklace of the-m, which brought thousands of pounds when sold at auction after the overthrew of tho Imperial dynasty. most sensitive instrument yet mado is the bolometer, which is used for measuring variations in the radiation of heat. The heart of'it is a platinum wire so thin that it cannot be seen except when. a. lay of bright light is reflected from it.