206 ANNUAL OF SCIENTIFIC DISCOVERT. 



filthy. The colder the water is, the greater the capacity to con- 

 tain these gases. At ordinary temperatures, a pail of water will 

 contain a pint of carbonic acid gas, and several pints of ammonia. 

 The capacity is nearly double by reducing the water to the tem- 

 perature of ice. Hence, water kept in the room awhile is always 

 unfit for use. For the same reason the water from a pump should 

 ahvnys be pumped out in the morning before any of it is used. 

 Impure water is more injurious than impure air. This shows the 

 economy and the convenience of a modern ice pitcher, a splendid 

 invention, which, as it seems, is more than ornament and show, 

 aye, it is really and absolutely a necessity. 



A NEW REAGENT. 



Professor Bottgerhas prepared a new and highly sensitive chem- 

 ical test for acids and alkalies, from the leaves of an ornamental 

 plant named, in honor of the Dutch horticulturist, Verschaffelt, 

 Coleus Vtrscliaffelti. The reagent is prepared by digesting the 

 fully developed leaves in alcohol, and impregnating slips of 

 Swedish filter-paper with the decoction. This test-paper differs 

 from litmus prepared from a certain species of lichen in hav- 

 ing a beautiful red tint, which becomes green under the influence 

 of an alkali or alkaline earth. It is not affected by free carbonic 

 acid, so that it may be used in detecting traces of carbonate of lime 

 in water. A strip of this paper moistened in water, and held over 

 a burner from which gas is issuing, assumes in a very short time a 

 green tinge, in consequence of the ammonia, from which, per- 

 haps, no gas is altogether free. 



PRESERVATION OF WINES. 



We translate from " L'lnvention " the following article by Mons. 

 Pasteur, on experiments made by him to find the causes of dete- 

 rioration of wines. If his views be correct, other liquids of veg- 

 etable origin maj 7 probably be preserved by the process he recom- 

 mends, lie says : 



" I have previously communicated to the Academy divers notes 

 relative to the changes which wine undergoes by age, and to its 

 causes of deterioration, and to the practical processes which may 

 be adopted for its preservation. The results of my studies may 

 be stated briefly : 1. Wine is changed from the state of new 

 wine to that of old wine almost exclusively by the influence of 

 the oxygen of the air. 2. Wine is not changed by any action 

 within itself, due to unknown causes. Whenever it becomes dete- 

 riorated, it is by the action of parasitic vegetations that are devel- 

 oped under diverse influences. 3. The deposits in wine are caused 

 exclusively either by oxidation produced by the oxygen of the 

 air, "or by the parasites, or, more frequently, by both combined. 

 4. The deposits clue to the influence of oxygen in most cases ad- 

 here to the vessel ; and those due to parasites always float, and 

 are consequently injurious, both chemically and physically. 5. 

 The problem to be solved for the preservation of wines, therefore, 

 consists solely in preventing the development of the parasites; in 



