SCIENTIFIC.

Otago Witness, Issue 1796, 24 April 1886, Page 28

SCIENTIFIC.

— Scientific investigators have found that the power of the bacillus of'con.sumxjtion is destroyed when other bacteria are grown in the same soil. Recognising this fact, tho new and remarkable idea has occurred to Dv Canlani, of Naples, of fighting bacilli wioh other bacilli. If one of the organs of tho body be attacked by a bacillus which is dangerous to human life,he ntroducesa bacillus which is not dangerous to man, but brings destruction to the dangerous bacillus. In the case of a consumptive patient, the doctor introduced a harmless organism known as the bacterium tertno, and found that the bacillus tuberculosis gradually disappeared from the patient's expectorations. — We have alluded more than once to the magnificent work which is being clone in connection with tho Paris Observatory by the brothers MM. Paul and Prosper Henry, whose optical factory has turned out some of the finest telesnope-onjectives ever made. Not long since the brothers Henry completed an objective of 13^in aperture, designed expressly for celestial photography, and the mounting and fitting i f this instrument, together with the driving machinery by which the instrument is kept constantly pointing to any given part of the sky, are of the most refined and delicate construction. When a sensitive dry plate is placed in the darkslide, which is fitted to the lower end of the telescope-tube (occupying the position of the eye), the images of the stars, &c, are received on tho film, and it is found that au exposure of from one to two hours' duration is sufficient to secure a record of stars down to the 15th or 16th magnitudes — staro below the sixth magnitude being invisible to the naked eye. But the most remarkable discovery yet made is that there exist in the heavens bodies capable of impressing their images on a sensitive plate, but which have never, as yet, been seen through nny telescope, and which cannot even be seen through the s.ime telescope by which they are photographed. Tho star cluster called the Pleiades is one of the most famous in the heavens. To the nnk. j d uyc il shows some six or seven stars, but fchu teleocope reveals many more. These >tar.-3 have been mapped, and the cluster lias been carefully studied with the ; reatest care and with tho mo.-t powerful instrument*-, by many famous astronomers. Vt r e can imagine, then, the siii-prino of the Parisian astronomer* when. Oil November G last, they --aw, on davelopini; a negative which had bjfii expose.; to the lighL of the Fluiadee, not. only all bin* "t-Hri with whose presence they were already familiar, but anew nebula. To prevent the possibility of any mistake, the same region was again photograped on December 8 and 9, and identically the same results were obtained. The now body is described as being of a diameter of three minutes, very intense, and presenting a well-marked shape — a shape which is characteristic of ma. y nebnlse. Its exact positon in the sky is right iivj.)nsion, 3hrs. 38min. 57sec. ; declination, z-ldeg. limn, north. It will now be a matter of the; hi jhest interest to ascertain whether this nebula is visible through more powerful telescopes', such has the famous refractor at Washington, the diameter of whose object glass is 26 inches. The nature of the light emitted, too, which is able so powerfully to impress its image on the dry plate, while it cannot affect the nerves of the eye, must bo a matter of great interest, though we fear that, from the feebleness of it light, its may be impossible to examine it through the spectroscope ; still, that insturment used in connection with a camera may give indication of its nature. The position which photography is assuming it connection with astronomy is, indeed, of the highest importance ; and it must be a matter of gratification to every photographer that his favourite art is able to render such valuable aid to this the oldest of the sciencesr — Photographic News.

— No question ha« attracted more attention from scientific agriculturists and vegetable physiologists than that of finding whether plants can get any of their stock of nitrogen from the air. Hitherto it has been held that they can, but only by a roundabout process. Thunderstorms are supposed to convert the nitrogen into nitric acid and ammonia, which are dissolved in falling rain, and are carried into the soil for plants to absorb by their root?. But careful estimates of the actual amount of nitrogen that enters the soil in this manner showed that it could never keep land on which even grass for grazing only was grown from getting exhausted. Tho conclusion was hastily drawn that the amount of nitrogen free to circulate amongst animals and vegetables was strictly limited to that already iv circulation, and a time was im-

agined when the human race could no longe increase, simply because the whole available supply of nitrogen would be in circulation with not one scrap of reserve. M. Berthelot, the famous French chemist, has added another to the long list of his valuable discoveries by findiug that in clayey soils there is an organism which can extract the nitrogen from the air and fix it; and although he has not been able to separate the organism or see it under the microscope, he has proved that it is subject to all the conditions ot ordinary vegetation — it is inactive in winter and is killed by a very high temp e rature.

_ — A correspondent writes to us : " When in Vicksburg, lately, si cotton-planter there gave me some interesting .particulars as> to the means adopted for preventing the plague of the army worm. This worm is the larva of an iusect which is very destructive to the notton-plant, and often strips whole acres nearly bare of foilage. At the time when the moth or butterfly, which is the product of it, is on the wing, an electric light is suspended over a large flat vat containing molasses or oil. The moth is attracted by the light, and after fluttering round, settles down, as ifc supposes, on the ground, but really in the oil or molasses, which drowns it. They tell me that one light is sufficient for 20,000 acres of land, and that in this way they can now control the army worm." — Home Patier.

— Up till quite recentty the accepted theory as to the action of yeast in bread-making has been the yeast produces a genuine spirituous fermentation in .some of the constituents of the flour, but of late jeirs there hns been a disposition on the part of some chemists to question this. M. Girard, a French chemist, who has devoted a good deal of attention to the chemistry of bread-stuffs, hasmadesome extensive analyses, which prove that it is by alcoholic fermentation that bread is raised. Iv the manufacture of 300 21b loaves more than a pint of alcohol is produced, The pleasant smell of bakery must be partly owing to this.