space" as fragments of a shattered world, was a most heroic speculative venture, seeing that we have no evidence whatever of any world of any sort ever having been shattered at all, still less of its having been shattered so gently as to permit its fragments to travel about bearing uninjured seeds.

The old theory which ascribed the asteroids to the fracture of a large planet has been long since disproved by the distribution of their orbits.

We marvel at the mummy wheat so long preserved amid careful enfoldings in the pyramid; but what is a few thousand years to cosmic periods? and what must be the hardihood of seeds that could exist all this time in vacuous space and still retain the aqueous constituents essential to their vitality?

Besides possessing this vitality, they must have been absolutely fireproof to have endured the heat which we now know, and also knew in 1871, is developed by the collision of meteoric bodies with our atmosphere.

Sir William Thomson has now a rival in Professor Hahn, of Berlin, who has written a book, illustrated with many plates, to prove that certain meteors contain the skeletons of sponges, corals, encrinites, &c., &c. The maintenance of such calcareous and siliceous skeletons, if formed, is conceivable, the conditions under which their existence as mere fossils may be maintained being so different from those demanded by a living germ.

But even these are evidently illusions, as Carl Vogt, Professor Lawrence Smith, and others have shown. They are well-known crystalline structures that have been observed and described again and again by mineralogists, many having specific names that I need not here repeat.

Even when dealing with the minerals of our own globe, we come to structures that are very equivocal. The Eozoon Canadense, the "creature of the dawn," which is commonly described as a sort of geological Adam, the beginner of life on our globe, has been ascribed by able observers to siliceous minerals, "simply affected by partial erosion and replacement, having become shaped into a variety of residual conformations that have been mistaken for organic structures."

The Eozoon controversy has been maintained in a very lively fashion since 1855, when W. King, Professor of Mineralogy and Geology, and Dr. Rowney, Professor of Chemistry in Queen's College, Galway, proclaimed the above-stated heresy. Dr. Carpenter has warmed the discussion haracteristic description of the

"audacity" of the "two Galway professors" and their "shocking state of ignorance of foraminiferal structure," &c. These two professors have lately published a book on the subject ("An Old Chapter of the Geological Record"), in which they stoutly reiterate and further illustrate their reasons for denying the existence of this interesting "creature of the dawn." I am not competent to take up either side of the controversy, but can see plainly enough that the professors have fairly justified their audacity in raising the very interesting question. I have known Dr. Rowney since his youthful days, and worked in the Edinburgh laboratory, where he was then an assistant. His reputation for conscientious accuracy was so well established, even then, that we used to say that "anybody may swear to any of Tom's analyses." Whether the Eozoon is the "creature of the dawn," or only a result of the methylosis of metamorphic rocks, Dr. Carpenter's high-handed assumptions are unjustifiable, and the rescarches of the "two Galway professors" demand respectful consideration. They describe mineralogical and chemical structures which they have studied with scrupulous care and thoroughness, and in reference to which they are high authorities.

THI

PROFESSOR BARFF'S ANTISEptic.

HE subject of one of my Notes in March 1881, page 377, was Disinfection and Boric Acid," to which I now refer my readers, as the subject has lately been brought forward by Professor Barff, who has obtained a very interesting true chemical compound of this acid with glycerine, or, more strictly speaking, glyceril, which is glycerine minus water. The compound in question is formed by simply boiling together equivalent proportions of boracic acid (or boric acid, the same thing with another name) with glycerine, till all the water is driven off, and there remains a crystalline compound curiously resembling ice, to which the name of "boroglyceride" is applied.

He read a paper at the Society of Arts on March 29, and showed specimens of meat, &c., which had been preserved in a fresh untainted condition by using a solution of this compound. The subject has been taken up by the newspapers, and many people are much astonished at Professor Barff's results. None of these samples, however, were nearly so remarkable as that which I described in the above-named Note. The carcase of the horse, which my friend Robottom used as a sofa, had been preserved perfectly fresh during seven months, although exposed to the full glare of the sun in a

climate where the thermometer reaches 119° in the shade, and where beef and mutton become offensive in a few hours after slaughtering.

This really was a discovery, and for some two or three years past both boric acid and its soda compound have been advertised and sold for the purpose of meat-preserving, and as general antiseptics. It is also well known that glycerine has similar properties, which also have been practically applied.

There is, however, an element of novelty in Professor Barff's proposal to combine these and use them as the boroglyceride compound above described. Nature, April 6, describes this as "an ether of boric acid and glycerine," first obtained by Schiff and Becchi; states that Barff's chemical description is inaccurate; and further, that there can scarcely be any advantage in forming the ethereal compound, as it is decomposed into boric hydrate and glycerine on contact with water.

Whether the compound in question is "an ether of boric acid and glycerine," as the writer in Nature asserts, or whether it is "a body analogous in its composition to fats," and "consists of glyceril united with boracic acid instead of with a fatty acid," as Professor Barff asserts; whether its composition be BO3 C, H, or C3 H5 BOз, is one of those solemn struggles of Tweedledum v. Tweedledee that may be advantageously left to the championship of the molecular changeringers, described in one of my "Science Notes" of October 1880.

5

The really important question is whether this antiseptic may be habitually used in admixture with our food without producing any derangement of health. This is not to be answered simply by ascertaining the action of uncombined boric acid, which may possibly be mischievous, while the boroglyceride is perfectly harmless, as in the case of chloride of sodium or common salt. Chlorine and hydrochloric acid are both acrid poisons, but their compound is harmless and even necessary.

Then there is the question of practical quantity. In ordinary spring water we drink a greatly diluted solution of several salts, that in a larger quantity and more concentrated solution would be very mischievous. This may be very probably is-the case with the boroglyceride. We therefore require to know how much will be contained in the quantity of meat we take at a meal. If the dilution is so great that it is held freely in solution in the fluids of the body, and is chemically inert, it may pass from the body as freely as the salts which our ordinary drinking water dissolves from the rocks and soil through which it passes.

The paper read at the Society of Arts does not make this clear,

nor whether this antiseptic is effective when acting only superficially; or whether it is necessary that it should penetrate throughout the meat in order to preserve it. This is an important question, as, in the first case, simple washing would remove it, or greatly reduce its quantity.

Then there is roasting v. boiling, just as in ordinary salted meat. If the reader desires to understand this difference practically, let him order from his butcher a piece of salt beef for boiling, and have it roasted. When roasted, all the salt remains; when boiled, a large proportion is dissolved out. It would be an interesting experiment to prepare-say, a round of beef-by Barff's method with a pickle containing a weighed quantity of the antiseptic, then to ascertain how much of this is taken up by the meat, and after this boil the meat, determine the quantity of boroglyceride in the water in which it was boiled, subtract this quantity from that originally in the meat, and then divide this by the fraction of the joint consumed by one person at one meal.

The object is so important that its thorough investigation is worth any amount of labour. If the primeval savage was able to discover in chloride of sodium a harmless antiseptic salt, capable of preserving "mess pork" and "salt junk" in an eatable condition, the modern chemist ought to be able to discover some improved pickle that shall carry us the very small step further which alone is required to render the beef and mutton of the prairies and antipodes quite unobjectionable, and importable as cheaply as pickled pork.

The preservation of anatomical specimens in which flavour is no object will probably be adopted at once. For these a concentrated solution is freely available.

L

THE FATE OF A SUN-COLLIDING COMET.

AST month, on page 503, I postponed the discussion of a question which then arose, viz., the probable effect of direct cometary collision with the sun, on the comet itself.

Assuming, for the reasons stated in the Note on the constitution of comets, that they are mainly composed of a hydrocarbon, similar to paraffin, the first effect of approach to the sun would be a vaporisation and expansion of the substance, with the consequent outspreading already described. On nearer approach to the sun it would be heated to what is now technically termed in the petroleum market "the flashing point," ie., the temperature at which it bursts into flame when exposed to a supply of oxygen. This tem

perature varies directly with the amount this supply, and inversely with the density or specific gravity of the parafin. If the sun is surrounded by an atmosphere containing oxygen. 1s we have good reason to believe that he is, combustion would occur at some considerable distance from the visible sclar surface.

I will not venture upon any definite estimate of that distance, beyond stating that many of the best known comets must have come within it when at perihelion, and expressing the probability that the mysterious and very flame-like appearances and movements presented by the heads of comets when at their nearest to the sun may really be ordinary vulgar flames, limited in octburst by scant supply of oxygen, and deficient in brilliancy on account of the rarity of both the hydrocarbon vapour and of its surrounding atmospheric matter.

Supposing the combustion of our directly colliding comet to be completed on reaching the solar photosphere, what would then happen?

The bombarding material would be a great gas bubble, a swiftly rushing blast of carbonic oxide, carbonic acid and aqueous vapour. On plunging into the photosphere it would dash its flames aside, producing a huge and ragged sunspot bordered by billows of outdriven flaming matter, i.e. "facula" and outflashing prominences. Then the comet-gases would plunge into the regions of dissociation, and there be dissociated accordingly; the aqueous vapour absorbing or rendering "latent" 8,000 degrees of the heat simultaneously generated by its arrested motion. The carbon and oxygen compounds would be similarly dissociated with a similar, but smaller, loss of temperature, the total amount of this loss corresponding to the heat evolved by the previous combustion of the hydrogen and carbon.

Another comet is making its way towards the sun and the earth. It appears to be a new one, and will probably be visible without telescopic aid at about the time of the publication of this Note.

Two comets visible at the same time by the naked eye in one year, and another early on the year following, is a rare exuberance of astronomical luxury. We have three or four telescopic comets during ordinary years; last year there were six altogether. Is our solar system, in the course of its flight through space at the rate of nearly half a million of miles per day, plunging into a region unusually rich in comets? If so, we may have some interesting opportunities of practically studying some of the questions I have hypothetically discussed in this and previous Notes.

W. MATTIEU WILLIAMS,