BIOLOGY. 295 



London, and Liverpool, in some cases to so great an extent as to 

 cause the occupants to leave them." As to our chinch-bug, our 

 curculio, our pluni-gouger, our two principal apple-tree borers, our 

 eanker-worm, our apple-tree tent-caterpillar, our fall web-worm, 

 our peach-tree borer, and our other indigenous pests among the 

 great army of bad bugs, nobody ever yet found a single one of 

 them alive and kicking on the other side of the Atlantic. And 

 with regard to plants, the only two American plants that we know 

 to have become so firmly established in Europe as to be a nui- 

 sance there, are an American aquatic plant, the common water- 

 weed (Anacliarsis canadensis), which has choked up many of the 

 canals in England, and our common horse-weed, or mare's tail as 

 it is called in the West (Erigeron canadense), which has spread 

 from America nearly over the whole world. From the Report of 

 Charles V. Riley, State Entomologist of Missouri. 



ATMOSPHERIC OZONE. 



From the proceedings of the Institute of Lombardy, reported in 

 the "Imparziale" of the 16th May, we extract the following re- 

 sults of the important experimental researches of Professor Mante- 

 gazza on the action of the essences of flowers on the production 

 of atmospheric ozone. 1. The essences of mint, turpentine, 

 cloves, lavender, bergamot, anise, juniper, lemon, fennel, nut- 

 megs, cajeput, tlvyrne, cherry, laurel, in contact with atmospheric 

 oxygen in light, develop a very large quantity of ozone, equal if 

 not superior in amount to that produced by phosphorus, by elec- 

 tricity, and by the decomposition of permanganate of potash. 



2. The oxidation of these essences is one of the most conven- 

 ient means of producing ozone, since even when in very minute 

 quantity they can ozonize a large quantity of oxygen, whilst their 

 action is very persistent. 



3. In the greater number of cases the essences, in order to de- 

 velop ozone, require the direct rays of the sun ; in a small num- 

 ber of cases they effect the change with diffused light ; in few or 

 none, in darkness. 



4. In some cases, however, the action just commenced in solar 

 light was found to persist to some extent when the essence was 

 placed in darkness. 



5. In some cases a vessel perfumed with an essence, and after- 

 wards thoroughly washed with alcohol and perfectly dried, could 

 still develop a proportionate quantity of ozone, provided that it 

 retained a slight odor of the essence. 



6. The essences that developed the largest quantity of ozone 

 were those of cherry, laurel, palmaroza, cloves, lavender, mint, 

 juniper, lemons, fennel, and bergamot ; those that gave it in less 

 quantity were anise, nutmeg, cajeput, and thyme. 



7. Camphor, as an ozonogenic agent, is inferior to all the above- 

 named essences. 



8. Eau de Cologne, honey-water, and other perfumes, or aro- 

 matic tinctures, develop a proportionate quantity of ozone when 

 they are exposed to the direct rays of the sun. 



