246 



♦ KNOWLEDGE ♦ 



[Oct. 19, 1883. 



FISH AND PHOSPHORUS. 



By W. Mattieu Williams. 



A CURIOUS notion concerning fish diet is widely pre- 

 valent. It is supposed to sup))ly special brain food. 

 If this were true the Dogger Bank fishermen, who feed on 

 cod-fish, should be intellectual giants. I sailed for two 

 months in a schooner, the skipper, the mate, and half of 

 the crew of which had for many years eaten cod-fish at every 

 meal. They were by no means remarkable for cerebral 

 activity, nor ai-e the rest of their class. 



The popular fallacy seems based on a series of other 

 fallacies. First, that there is something very spiritual in 

 phosphorus ; second, that phosphorus is a special and 

 ■exclusive constituent of the brain ; and third, that fish 

 contains more phosphorus than other food materials. 



The first is mere imaginative nonsense. The second is a 

 half-truth. Phosphorus is a constituent of cerebral and 

 other nervous matter, but it is also a constituent of bone, 

 ■which contains aViout eleven per cent, of phosphorus, while 

 brain matter contains less than one per cent. 



The third fallacy seems to have originated in that very 

 common source of error — viz., dependence on mere words. 

 Fishes are remarkably phosphorescent — ergo, says the 

 word-slave, they must abound in phosphorus. 



The fact is that the chemical element named phosphorus 

 has nothing whatever to do with the phosphorescence of 

 fishes, nor with that of the multitude of other phosphores- 

 cent animals. The glow-worms (of which there are many 

 species in England alone) and the numerous insects in- 

 cluded under the general name of fire flies are brilliantly 

 phosphorescent without the aid of phosphorus. The 

 minute jelly-like creatures that at certain times render the 

 crest of every breaking wave a blaze of light, and mark the 

 course of porpoises and bonettas with pale rocket-like trails, 

 are animals in whose composition phosphorus is especially 

 lacking. 



The true connection that exists between the luminosity 

 of phosphorus and that of organic phosphorescence is that 

 both are dependent on slow or languid chemical combi- 

 nation, while vivid combustion is a manifestation of 

 intense or vigorous chemical combination. Ordinary com- 

 bustion is a vigorous combination of something with 

 oxygen ; the phosphorescence of phosphorus is due to a 

 slow oxidation of this element, and it is probable that the 

 other cases of phosphorescence are due to the slow oxidation 

 of something else. 



B. Radziszewski has recently investigated this subject, 

 and concludes that the phosphorescence of organic bodies 

 is produced by the action of active oxygen in alkaline 

 solution. (Ozone is another name for active oxygen. ) He 

 describes two kinds of organic phosphorescent matter, 

 the first of which contains hydrocarbons, and the second 

 aldehydes, or yields aldehydes when treated with alkalies. 



According to this, all phosphorescence is a result of slow 

 combustion, like that which produces animal heat, or the 

 heating of a damp haystack or other heap of vegetable 

 matter and water. 



As heat and light are both due to internal activities of 

 matter, differing only in a manner analogous to the diffe- 

 rence of motions of the air produced by the difference of 

 the vocalisation of Santley and Patti, the mystery of Will- 

 o'-the-Wisp, of oceanic phosphorescence, glow-worm light, 

 <fec. , is no greater than that of the warmth of our own bodies. 



The anomaly of phosphorescent light is that it is ac- 

 companied with no sensible elevation of temperature, while 

 ordinary combustion, when it rises to the pitch of effecting 

 luminosity, is accompanied with intense heat. 



There must be an essential difference between the waves 

 of white light emitted by incandescent platinum or white- 

 hot carbon, and those from the glow-worm. I am not 

 aware that mathematicians have satisfactorily fitted the 

 undulatory theory of light to the explanation of these 

 difi'erences. — Gentleman's Magazine. 



Persons who fancy that wetting coal increases the heat 

 in the furnace may be interested to know that a series of 

 tests was made recently at Boohum, Germany, to determine 

 the values of wet and dry bituminous coal in making 

 steam. According to the American Mechanical Engineer, 

 washed slack, holding 18 per cent, of water and 9 9 per 

 cent, of ash, evaporated 5 7 lb. of water per pound of fuel ; 

 while the same coal, with only 3 per cent, of water, made 

 from 8 to 8 -5 lb. of steam. Making due allowance for 

 moisture by reducing to a standard of like quantities of 

 coal from moisture, there is found to be a direct loss, by 

 using wet coal, of 14 per cent 



Organic Compounds in the Sun. — The third volume 

 of the Royal Engineers' Institute Occasional Papers, re- 

 cently published, contains a very interesting communication 

 from Captain Abney, upon a new method of spectroscopic 

 analysis as applied to the investigation of solar physics. 

 Captain Abney's and Colonel Festing's combined investiga- 

 tions referred to that part of the spectrum lying beyond 

 the extreme visible limit at the red end, the energy of 

 which can be made apparent under certain conditions, and 

 the dark lines beyond this limit may be photographed and 

 thus accurately mapped out. As an illustration of the 

 practicability of this. Captain Abney described a very 

 beautiful experiment suggested by the permeability of 

 ebonite to the energy of certain rays, as shown by experi- 

 ments with the photophone. He arranged an arc light so 

 that the image of the carbon points and of the arc were 

 thrown on the focussing screen of the camera, and he then 

 interposed between the light and the plate, which was 

 sensitive to dark i-adiation, a screen of ebonite. The 

 success of this interesting experiment proved that 

 ebonite is transparent to the dark rays beyond the 

 red end of the spectrum. Experiment showed that 

 in this region very few metals have any lines, those 

 fusing at very low temperatures, such as sodium, po- 

 tassium, and calcium alone giving indications, and this 

 suggested that the dark lines seen must be due to other 

 and probably compound bodies. Commencing with water, 

 Captain Abney and Colonel Festing examined the spectra 

 of a large number of compounds, some of them highly com- 

 plicated, and after their experiments had been completed, 

 they compared the spectra they had obtained with the solar 

 spectrum. The coincidence observed by these comparisons 

 led to the " inevitable conclusion that we must have some 

 derivation of benzine and ethyl present either in our atmo- 

 sphere or in the sun." Solar spectra taken at different 

 times of the day proved the former supposition to be un- 

 tenable, although Captain Abney states that recent experi- 

 ments lead him to believe that such derivations exist in 

 space. These investigations largely confirm, and are con- 

 firmed by, those of Dr. Huggins, on the composition of 

 cometary matter. Dr. Huggins has shown by the spectrum 

 the existence of hydi'ocarbons not only in comets, but also 

 in nebulous matter, and his results accord with those of 

 Captain Abney and Colonel Festing, whence Captain Abney 

 deduces "that there is no doubt whatever in my mind that 

 as spectroscopic science advances, so we shall be able to 

 place more and more compounds in the stars, in the sun, 

 and in cometary matter." — Engineering. 



