Part 16

PETROLEUM united to acid of amber.

CRONSTEDT Min. §§ 133–146. Succinum. Amber.

Many contend that amber has a vegetable origin; but as the point is not very well determined; and as it is found amongſt foſſils, I ſtill retain it here.

§ 141.

AMBERGRISE, according to the aſſertion of Mr. AUBLETT, is nothing more than the juice of a tree inſpiſſated by evaporation into a concrete form. This tree grows in Guyana, and is called Cuma, but has not been inveſtigated by any botaniſt. Pieces of this tree are ſaid to be carried down into the rivers by heavy rains, and the ſpecimens examined by Mr. ROUELLE had the odour and principal qualities of amber. RUMPHIUS, long ſince, mentioned a tree called Nanarium, whoſe juice reſembled amber.

DIAMOND.

§ 142.

At firſt ſight I may ſeem to have acted erroneouſly, by ſeparating this from the other gems, and inſerting it here; but after due conſideration, I know not where to place it better. It has never yet been decompoſed by the liquid analyſis; and when expoſed to the fire in an open veſſel, it is wholly conſumed, burning with a lambent flame. This deflagration, though ſlow, ſhews decidedly its affinity to the inflammables: beſides, in the focus of a burning glaſs, it leaves traces of ſoot. When further experiments teach us better, I ſhall willingly correct my error.

CLASS IV. METALS.

§ 143.

I have before mentioned the great affinity betwixt metallic and inflammable ſubſtances (§ 133). Zinc and arſenic stand, as it were, upon the borders betwixt them; for these, in proper circumſtances, burn with a very evident flame. All the metallic ſubſtances contain phlogiſton, and when, to a certain degree, deprived of it, fall into a powder like an earth; but their attractions for phlogiſton are different. Moſt of them, when melted in a common way, and expoſed to the air, have an earthy cruſt formed upon the ſurface, which cannot again be reduced to metal without the addition of ſome inflammable matter. The baſe metals, eleven in number, have this property: but the noble metals, platina, gold and ſilver, are ſo firmly connected to the phlogiſton, that they never calcine under fuſion, however long continued; and after being changed into a calx in the liquid way, when melted in the fire, they re-aſſume their metallic form, without any other phlogiſton than what is contained in the matter of heat.

Quickſilver holds a kind of middle place; for, like the baſe metals, it may be calcined, though not readily; and like the noble ones, it may be reduced by heat alone.

I have placed each diviſion of the metals in the order of their specific gravities.

Thoſe metals, which are found in a perfect metallic ſtate, are called native; thoſe united to acids, or to ſulphur, are ſaid to be mineralized; and thoſe which are only deprived of their phlogiſton, calciform.

TABLE OF METALS. │ │ │ │ Attraction METALS. │ │ Specific Melting Saturating to │ │ Gravity. Heat. Phlogiſton. ſaturating │ │ Phlogiſton. Gold │ │ 19,640 1301 394 1 or 2 Platina │ │ 21,000 756 1 or 2 Silver │ │ 10,552 1000 100 3 Quickſilver│ │ 14,110 −39 or −634 74 4 Lead │ │ 11,352 595 43 10 Copper │ │ 8,876 1450 312 8 Iron │ │ 7,800 1601 342 11 Tin │ │ 7,264 415 114 9 Biſmuth │ │ 9,670 494 57 7 ───────────┼───────────┼─────────────────────────────────────────────── Nickel │ common │ 7,000 1301 156 11 „ │ pure │ 9,000 1601 „ „ ───────────┼───────────┼─────────────────────────────────────────────── Arſenic │ │ 8,308 109 5 ───────────┼───────────┼─────────────────────────────────────────────── Cobalt │ common │ 7,700 1450 „ │ pure │ „ 1601 ───────────┼───────────┼─────────────────────────────────────────────── Zinc │ │ 6,862 699 182 11 Antimony │ │ 6,860 809 120 6 Manganeſe │ │ 6,850 very great 227 11

AURUM, OR GOLD.

§ 144.

The ſpecific gravity of this metal, when pure, is 19,640. Aqua regia diſſolves it; but except the dephlogiſticated muriatic acid, and in certain circumſtances the nitrous, no ſimple acid acts upon it, unleſs it has been previouſly calcined. The quantity of phlogiſton neceſſarily taken away in the ſolution of 100 parts of gold, I eſtimate at about 394; whilſt the ſame quantity of ſilver, loſes by ſolution in the nitrous acid, 100. Gold retains the phlogiſton neceſſary to its metallic form, more obſtinately than any other metal, except, perhaps, platina. It melts and calcines in the focus of a burning glaſs at 1301 degrees of heat.

§ 145.

AURUM nativum (gold native) united to ſilver.

Native.

I do not know that gold has ever yet been found perfectly pure.

§ 146.

AURUM nativum (gold native) united to copper.

Native.

§ 147.

AURUM nativum (gold native) united to ſilver and copper.

Native.