668 Chronicles of Science. [ Oct., 
voyages. We should recollect that the Calluna advances to the extreme 
western limits (or out-liers) of Europe, in Iceland, Ireland, and the 
Azores. The step thence to Newfoundland and Massachusetts, though 
wide, is not an incredible one.” 
Without doubt these are the very specimens referred to by Mr. 
Don, then curator of the Linnean Society ; and now that the stations 
where they were collected are made known, we may expect that 
the plant will soon be rediscovered, and its indigenous character 
ascertained. 
M. Cahours finds that fruits, such as apples, oranges, and lemons, 
after being pulled, absorb a portion of oxygen from the air, and give 
out carbonic acid. The quantity of the CO, given off is greatest in 
darkness and at a high temperature. Similar phenomena take place 
when the fruits are placed in oxygen gas. When the fruits begin to 
decay, then a large quantity of CO, is formed, so that the atmosphere 
around the fruits becomes loaded with it and very unwholesome. This 
occurrence depends on a chemical change in the juices of the fruits. 
Carbonic acid is given off by decaying fruits when placed in azote, 
proving that it 1s not produced by absorption of the oxygen of the air. 
The change in medlars, called by Lindley “ bletting,’ is similar, and 
is accompanied with fermentation, causing sugar to be converted imto 
alcohol, carbonic acid, and an ether which gives the peculiar aroma to 
the fruit. 
Dr. Seemann has made a list of 279 species in which double flowers 
occur. Of these, 234 are exogens and 45 endogens. Of the exogenous 
species, 166 are polypetalous, 66 gamopetalous, and 2 apetalous. The 
vast majority of plants producing double flowers occur in the Northern 
hemisphere. Notasingle species with double flowers has been noticed 
in Polynesia and Australasia. A few occur in South Africa and South 
America. 
Mr. Carey Lea, of Philadelphia, finds that ozone checks the growth 
of the roots of plants, and that it prevents the formation of mould. 
The ozone which he used was generated by the action of sulphuric 
acid upon chameleon mineral. 
Tt has been found that vegetable ivory in contact with concentrated 
sulphuric acid assumes a fine red colour, almost equal to magenta. At 
first it is pink, but gradually becomes deeper until it attains a purple 
when the acid has been allowed to act for twelve hours. 
Professor Braun, in the ‘ Proceedings of the Berlin Academy,’ 
gives a list of 387 species of Marsilea. Of these, 4 are found in Europe, 
Northern Africa, and Asia; 6 in Southern Asia; 12 in Central and 
Southern Africa and the islands adjacent; 9 in North and South 
America—one of which is common to both North America and Europe ; 
5 in Australia; and 4 in the South Sea Islands—only 2 of which, how- 
ever, are peculiar to them. 
Neotinea intacta of Reichenbach, an orchid allied to Aceras and 
not unlike Habenaria albida, has been recently added to the Irish 
