1056 Transactions of tub American Institute. 



signals to be transmitted all round the coast of England so as to fore- 

 warn seamen of the approach of a storm. 



Dr. Tillman.— The admiralty forecasts of the weather have been 

 found to be so generally incorrect that they have been given up. A 

 very good hygrometer for rough purposes may be made of human 

 hair, wlialebone, rye straw, etc. 



Mr. Stetson inquired about the camphor storm-gauge. It was 

 generally agreed that it was Avorth nothing. It indicates changes of 

 temperature alone. 



Mr. Blanchard described a hygrometer made of a tendril of some 

 plant. 



Dr. Smith referred to the use of a live tree toad as a storm-gauge. 



Dr. Feuchtwanger. — There is a small ladder placed in the jar with 

 the toad. During dry weather the toad descends into the water, but 

 climbs up the ladder on the approach of rain. 



The following interesting notes on scientific progress were presen- 

 ted by tlie chairman : 



A Copying Process. 



l^iepce St. Victor gives a new process for copying very old writings. 

 Ordinary copying paper is used, but is moistened with a thin solution of 

 glucose or honey, instead of water. On coming out of the press, the 

 paper is exposed to strong ammonia, which brings out very clearly 

 lines otherwise almost illegible. 



New Optical Glass. 



Messrs. Chance, of London, who have acquired the reputation of 

 making the best glass in the world for optical instruments, are now 

 engaged in manufacturing an entirely new glass for photographic 

 cameras, whioli is said to have, what many will be inclined to doubt, 

 a density of 4.4. Its composition has not yet been given to the 

 public. 



Sea-Weed Charcoal. 



The London Chemical News states that this material, which is 

 prepared from the fine tangle of the Hebrides, is being extensively 

 used in England as a substitute for animal charcoal as a filtering 

 medium for water, for deodorizing sewage, clearing white glass, remov- 

 ing acidity from and decolorizing wines, and precipitating and decolor- 

 izing- vegetable alkaloids. 



