# Popular Science Monthly/Volume 42/March 1893/Notes

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White bread and fine flour are named by Sir James Crichton Browne as one of the causes of the increase of dental caries. Failing to eat as large proportions of bran as our ancestors did, we are deprived to a large degree of the fluorine which they contain. The enamel of the teeth has more fluorine, in the form of fluoride of calcium, than any other part of the body. Fluorine might, indeed, be regarded as the characteristic chemical constituent of this structure, the hardest of all animal tissue; hence a supply of fluorine, while the development of the teeth is proceeding, is essential to the proper formation of the enamel, and any deficiency in this respect must result in thin and inferior enamel.
On the reopening of an old mine at Bangor, Cal., a few months ago, flies were found in a dry slope connecting two shafts, all white except the eyes, which were red, and a white rattlesnake was killed. The animals had lived in the dry passages, where they had been supplied with air but not with light. A few of the flies, exposed to light in a glass case, recovered their proper color within a week.
A large dirigible balloon, intended to make headway against air currents of twenty-eight miles an hour, is being made in France. It will be similar in form to the La France of 1884-'85, but larger—two hundred and thirty feet in length and forty-three feet in its greatest diameter. It will weigh sixty-six pounds per horse power, and will be propelled by a screw in front with a rudder behind.
From various experiments respecting a connection between thunderstorms and the souring of milk, Prof. H. W. Conn draws the conclusion that electricity is not of itself capable of souring milk or even of materially hastening the process; nor can the ozone developed during the thunderstorm be looked upon as of any great importance. It seems probable that the connection between the thunderstorm and the souring of milk is one of a different character. Bacteria grow most rapidly in the warm, sultry conditions which usually precede a ​thunderstorm, and it will frequently happen that the thunderstorm and the souring occur together, not because the thunder has hastened the souring, but rather because the climatic conditions which have brought the storm have at the same time been such as to cause unusually rapid bacteria growth.
A vivid sketch was given by Prof. Gruber, of Roumania, in the International Congress of Experimental Psychology, of remarkable associations of color and sound which he had been observing for many years. To a small number among his best-educated patients the sound of the vowel e was accompanied by a sensation of yellow color, of i by blue, of o by black, and so on through all the Roumanian vowels and diphthougs, and to some extent with numbers. The same color was not always induced by the same sound in different persons, but the observations had been carefully tested.
The Superintendent of the Natal Observatory, in his report for 1890-'91, acknowledged his obligations to seven ladies, without whose zealous assistance, he says, the greater part of the astronomical computations, etc., would not have been carried out.
The programme of the sanitary exhibit to be held in connection with the Chicago Exhibition defines its purpose to be to show as adequately as possible the position in which the theory and practice of hygiene stand at the present day. The programme itself is a full one, and includes classes of physical exercise, alimentation, hygiene of dwellings, hotels, lodging-houses, etc., public baths and lavatories, and numerous other features entering into the detail of hygienic management.—In connection with this subject we notice a paper on Typhoid Fever in Chicago, by William T. Sedgwick and Allen Hazen, in which the disease is shown to have increased in the city at a fearful rate within recent years. The cause of the increase is attributed to polluted water supply, which efforts are now being made to remedy.
A new coating for the protection of metalwork and woodwork from the effects of the weather or of water is based on the adaptability of cotton-seed oil to unite with lead. Melted lead is poured into cotton-seed oil under continual stirring, and the mixture is allowed to cool. When the oil is poured off the lead will be found at the bottom, but reduced in weight by the absorption of a part of it in the oil. The operation is repeated, with the lead left at the end of each trial, five times. When cold, the oil has the appearance of thick varnish, and is ready to be applied with a brush or a sponge. This coating unites quickly and firmly with any material.
The price of platinum recently rose, under a speculative combination, nearly to that of gold. This stimulated the discovery of new sources of supply, and the price of the metal went down again. There are now forty mines along the course of a single river in the Ural. The grains of ore are obtained from the sand by washing. The metal as found is usually associated with gold, iron, osmium, iridium, and other rare metals, and has to be purified from them.
It is related by the British consul at Cadiz, Spain, in illustration of the perfection with which natural wine can be imitated by modern chemical methods, that he and a friend, visiting one of the native sherry cellars there, were given two samples of wine to drink which seemed to be almost identical; and were told that one was a natural product and very costly ($250 a bottle), while the other was a manufactured product, the market price of which was only a few cents a bottle. In making the imitation, the natural product is first analyzed, and the chemist, ascertaining the exact nature of its constituent parts, is able to combine them and thus nearly reproduce the original compound.
The longest balloon ride on record is described by M. Maurice Mallet, in L'Aéronaute. It was from La Villette, Paris, to Wahlen, in central Germany, and occupied thirty-six hours and ten minutes, from October 23 to the morning of October 25, 1892. The flight was disturbed by snow in the upper regions of the atmosphere, which melted in the lower. During one of its descents the balloon, as is characteristic of the border land, was stopped and examined by a Prussian guard, who had galloped after it for a considerable distance.
The celebration of the three hundredth anniversary of the beginning of Galileo's labors as professor in the University of Padua, December 6, 1892, was attended by the Americans, Prof. William James, of Harvard, and Prof. Allan Marquand, of Princeton. The commemorative oration was by Prof. Antonio Favaro, who has been for fifteen years a student of Galileo, and is editor of the national edition of his works. He spoke chiefly of Galileo at Padua. He was followed by about a dozen of the foreign delegates and some of the Italian delegates. University honors were conferred upon seven foreign scientific men, representative of their several nations, including Prof. Newcomb. Besides some memorial works published by the ancient Academy of Padua, and by the university, the students of the university are about to issue a collection of documents relating to the sojourn of the philosopher at Padua.
Herr Nagel has succeeded in localizing the sense of taste of sea anemones in their tentacles. A piece of sardine brought carefully to the tentacles of one of these animals was seized at once by the one touched, then by the others, and was swallowed. A piece ​of blotting paper saturated with sea-water and applied in the same way was not seized; when soaked in the juice of fish, it was seized with the same energy as the piece of fish, but was often given up ultimately without being swallowed; soaked with sugar, it was accepted more daintily; but if saturated with quinine it was refused, the tentacles drawing back. On the outer surface of the body, and on the part between the tentacles and the mouth, quinine had no effect; nor did several other drugs of similar properties. Meat placed within or near the mouth of a widely open animal was not noticed; it was seized only when the tentacles were touched.
Among some recently observed interesting results of application of cold, M. Raoul Pictet has found that at -150° all chemical reaction is suppressed. Thus, if sulphuric acid and potash are brought together at this temperature, they do not combine. Litmus paper, introduced, keeps its color. It is possible to restore energy to these substances by passing the electric current, and the current passes readily, whatever the substances; at -150° all bodies are good conductors. The disappearance of affinity at a low temperature can be utilized to get absolutely pure substances; and M. Pictet has thus obtained alcohol, chloroform, ether, and glycerin.
A law has been enacted in Ontario forbidding the spraying or sprinkling of fruit trees while they are in bloom with any mixture containing Paris green or other substances poisonous or injurious to bees. The object of the legislation is to protect the bees from harm, the honey from possible taint of poisoning, and to avoid possible obstacles to the complete fertilization of the fruit.
The Prussian Government has decided to introduce the use of the centigrade thermometer instead of that of Réaumur, which was still in use in some parts of the kingdom.
From a careful review of the characteristics as to inheritability of certain diseased conditions of the human system, Henry J. Tilden has drawn the conclusion that pathology, so far from offering any support to the hypothesis of the transmission of acquired characters, pronounces against it.
Among the congresses to be held at Chicago by the World's Congress Auxiliary of the Columbian Exposition will be an international conference on aërial navigation. Its objects will be to bring about the discussion of some of the scientific problems involved, to collate the results of the latest researches, to procure an interchange of ideas, and to promote concert of action among the students of this inchoate subject. The meetings will be held on the afternoons of August 1st, 2d, and 3d. The topics to be discussed will be arranged under the three headings of Scientific Principles, Aviation, and Ballooning.