146 



THE POPULAR EDUCATOE. 



Husconi, in order to trace all the steps by which a water-newt 

 advances from the egg to its perfect state. The egg was noted 

 on the 23rd of April, when it was deposited by the parent on a 

 leaf, and the daily changes were watched under the microscope 

 until the 6th of May, when the young newt was hatched. The 

 water was kept all the time at a temperature of about 70 of 

 Fahrenheit's thermometer. Want of space prevents us from 

 describing all the steps in the development of the animal, but 

 many readers can conduct a similar series of observations for 

 themselves. We will, however, note a few of the more im- 

 portant stages in the advance. In five days the head, gills, fore- 

 feet, and tail were first seen in the egg ; in four days more the 

 beating of the heart was noticed ; in another day the little crea- 

 ture moved in the egg ; and on the 5th of May the eyes were 

 clearly seen. On the next day the struggles of the imprisoned 

 reptile broke its shell, and the newt was hatched. The 

 second set of observations now began, by which the progress of 

 the animal was noted through all the tadpole stages to the fully- 

 developed animal. The little fish-like reptile secured itself by two 

 hook-like appendages to a leaf, and then seemed to go to sleep 

 for a day or two. On the 18th of May, twelve days after the 

 hatching, the newt measured about half an inch long ; the toes 

 of the fore-feet were formed, the gills appeared ; the tadpole was 

 able to swim actively, and even to catch aquatic insects. On the 

 28th of May it had grown to the length of an inch ; the hind- 

 legs appeared, and the toes of the fore-leg were nearly perfect. 

 On the 18th of June the tadpole reached its final stage, and then 

 began to change into the newt. The gills were gradually ob- 

 literated, the lungs formed, the ear-holes closed, and on the 27th 

 of July the reptile took the complete form of a water-newt. 



We must now pause to describe the ingenious method by 

 which the eft* secures the safety of her eggs, and shows herself 

 to be a clever mechanic. She selects a leaf of some water-plant, 

 deposits a single egg upon the under-side of the leaf, then with 

 her feet bends the leaf back, so that it forms a case or box for 

 the egg. But the leaf, thus doubled back, would soon straighten 

 .igain, and leave the egg unprotected. To prevent this, the 

 newt pours out a gummy fluid from her body, and glues the bent 

 part of the leaf to the other or lower portion. Thus a pro- 

 tecting receptacle is formed for the egg, where it is hatched in 

 security. The mode in which this leaf -nest is formed, and the 

 exact order in which all the stages of the work proceed, may 

 almost lead some to suspect that the newt " must be able 

 to reason." These bent and doubled leaves may often be seen 

 in places where efts abound, and by breaking three or four off 

 and putting them into a jar, with water not lower in tempera- 

 ture than 65 Fahrenheit, the reader may watch all the stages of 

 a newt's life. 



We must now make a few remarks on the eft's relative, the 

 once dreaded salamander. Never was an animal so hated with 

 so little reason. The salamander proper (Salamandra maculosa) 

 resembles the newts in form, but it dwells on the land, loving 

 cool holes under old walls, and the roots of trees. One quality 

 universally ascribed to this reptile was its power of living in the 

 fire. It was one of "the best proved facts" in natural history 

 that the salamander was the " lord of fire." Francis I. of 

 France showed his belief in the marvellous tale b7 adopting for 

 his device a salamander in the flames, thereby hinting to his foes 

 that he, like that fearful reptile, was indestructible. The wild 

 belief in some countries was that if a fire should ever be allowed 

 to continue burning for seven years, a salamander would be pro- 

 duced from such flames. This superstition, however, was not 

 the cause of the intense hate borne towards the salamander, but 

 it invested the animal with a dread mysteriousness. How could 

 such a notion continue through so many ages, when tne matter 

 might have been easily tested by throwing a salamander on the 

 fire ? People are not willing to put their superstitions to the 

 test, and there was one slight foundation of fact on which the 

 whole monstrous pile of error was raised. The salamander can 

 pour out a little watery fluid from its skin when excited, and on 

 some occasions this fluid may have damped for a moment the 

 flame of some fire, on which the animal may have been cast. 

 The poor salamander was also believed to have the deadly power 

 of poisoning, not only the whole fruit of a tree on which it might 

 creep, but the vegetation of a large district. Even innocent cows 

 were not safe from the malicious reptile, which sometimes 



* Headers will remember that the animal ia called both eft and newt. 



sucked their milk, robbing them and the irritated farmer by one 

 felonious act. The bite of the creature was deemed so deadly 

 that a proverb expressed the fears of men and the helplessness 

 of the physician. " If a salamander bites you, put on your 

 shroud," was the doleful counsel given to the luckless wight 

 who might have been scratched by the tiny teeth of this animal. 



Could no good, then, be obtained from the horrid creature ? 

 Yes ; the heart, worn round the neck, would preserve the wearer 

 from perils by fire ! The chemists of old times professed to be 

 able to turn the salamander to a wondrous use. The mode of 

 operation and the expected results may thus be stated : Catch 

 one of the reptiles, put it in a crucible on a fire, pour quicksilver 

 over the roasting animal ; then, if all went well, the metal would 

 be turned into gold ! But one caution was essential : the ope- 

 rator must be a man of pure mind and heart, or no treasure 

 would appear. The universal failure of the experiments speaks 

 little in favour of the moral condition of the old chemists. 



The reader will see, from the preceding remarks, how ignorance 

 has filled the minds of men with abject dread of nature. War 

 against the animal kingdom was the result. It is not the least 

 advantage of natural history that it has dispelled most of these 

 delusions, while it discloses innumerable wonders of structure, 

 and remarkable instances of animal ingenuity. 



LESSONS IN CHEMISTRY. XX. 



CLASS III. THE METALS OF THE EAKTHS. 



IN the third class of metals are those whose oxides have not 

 such marked basic properties as either of the preceding classes, 

 and they are therefore denominated inetals of the earths, not 

 alkaline earths. They are ten in number aluminum, glucinum, 

 zirconium, thorinum, yttrium, erbium, terbium, cerium, lan- 

 thanum, and didymium. None of the group present sufficient 

 interest to require our attention except 



ALUMINUM Or ALUMINIUM. 



SYMBOL, Al COMBINING WEIGHT, 27'4 SPECIFIC GEAVITT, 2'6. 



This metal may be obtained by decomposing its chloride by 

 the galvanic current ; but, as in the case of magnesium, an 

 easier method is found to bo by the agency of sodium. The 

 chloride, melted into vapour, is caused to pass over melted 

 sodium ; this latter metal appropriates the chlorine of the salt, 

 and the aluminum is deposited. It is a bluish-white metal, 

 remarkable for its lightness. It does not readily oxidise when 

 exposed to air. These properties have recommended it for tho 

 making of ornamental trinkets. It is capable of being drawn 

 out into wire and rolled into plates. When struck it gives a 

 clear musical note. It is but little affected by nitric, but dis- 

 solves with rapidity in hydrochloric acid, giving off hydrogen, 

 and forming the chloride ; thus 



2A1 + CHC1 = AljCl. + CH. 



Hence the metal is Triatomic. It promises to become of somo 

 value in making alloys. Ten of aluminum and ninety of copper 

 produce an alloy of great strength and elasticity tho " Alu- 

 minum bronze." Its appearance is very like gold. 



Alumina (A1 2 O 3 ) is the only oxide. It appears almost pure, 

 and in a crystalline state, in the precious stones corundum, 

 ruby, sapphire. Emery is another form of this substance. It 

 is also present in considerable quantities in clay, being originally 

 derived from the decomposition of felspar. For commercial 

 purposes it is got by treating a solution of soda-alum with 

 hydrochloric acid, which is evaporated to dryness and heated ; 

 the mass is then washed with water, and alumina remains. Its 

 chief use is in dyeing ; it possesses the property of combining 

 with certain organic colouring matters, and forming insoluble 

 pigments termed lalces. Most colouring matters will not re- 

 main in the fibre of the material ; when this is the case, the 

 cloth, etc., is soaked in a preparation of alumina, and then 

 dipped into a bath of the dye. By this means an insoluble 

 compound is formed in the fibre of the material, and the sub- 

 stance is dyed "fast." The sesquioxides of iron and chromium, 

 and the oxide of tin, are mordants as well as alumina. 



Aluminum Chloride (A1 2 C1 8 ). The process which would at 

 once suggest itself for obtaining this salt namely, of acting 

 on alumina with hydrochloric acid does not admit of being 

 practised, for -on evaporating, and heating the acid is driven off. 



The method devised by Oersted is therefore used. Alumina 



