Let us first call ds the element of the curve described by the corpuscle m during dt; this being done, we shall have Vdt ds; and therefore the preceding equation assumes this form s m pds cosine R smVdV = 0. Now let us suppose for a moment that the curve described by m is an inflexible line, that m is a moveable grain interwoven with this curve, that it traverses it freely, i. e. without being pressed by the re-actions of the other parts of the system, that it experiences at each point of this curve the same vis motrix as that with which it was animated in the first case; and that, finally, in this first case the initial velocity of m is K, while in the second it will be null at the first instant, and V after an indeterminate time t: this being done, by integrating the preceding equation, in order to have the state of the system at the end of the time t, we shall have for the first case s's mp ds cosine R V d V = 0, s' designating the sign of integration relative to the duration of the movement, while s is the sign of integration relative to the figure of the system: now, s's m sm V2

Vd V =

2

s's m

therefore the equation may be placed in

this forms's mpds cosine R sm V2 + C = 0; C being a constant added to complete the integral: in order to determine it, we shall observe that at the first instant we have V = K and s's mpds cosine R= 0; therefore

=

s m K2

2

-; therefore 2 s' smp ds cosine R

s m V1 sm K20: by the same reasons we have for the second case 2 s' s m pds cosine R sm V1 2 = 0, without a constant, because we suppose V as null at the first instant: taking away therefore this equation from the preceding one, reducing and transposing, we have s m V2 = s m K2 + s m V; that is to say, in any system of hard bodies the movement of which changes by insensible degrees, the sum of the active forces at the end of any given time is equal to the sum of the initial active forces, plus the sum of the active forces which would take place if each moveable particle had for its velocity that which it would have acquired by freely traversing the curve it had described, and supposing besides that it had

been

been animated at each point of this curve, with the same vis motrix which it there really experiences, and that its velocity at the first instant had been null.

It is this proposition which we call the principle of the preservation of active forces; and whence we may conclude that,

In a system of hard bodies the movement of which changes by insensible degrees, and which are not animated with any vis motrix, the sum of the active forces is a constant quantity, i. e. the same for every instant.

For in this case we have by hypothesis p = 0, which gives V' = 0, and therefore s m V2 = s m K2; an equation besides which is extracted immediately from that s m p V d t cosine Rsm V dV 0, found in XXIV, which, on account of p = 0, is reduced to s m V d V = 0, the integral of which completed iss m V2 = 4 s m K2 = 0; whence follows the equation s m V2 = 's m K2. Q. E. D.

[To be continued.]

LX. On Chemical Nomenclature. By a Correspondent.

SIR,

To Mr. Tilloch.

THE importance of an accurate and scientific nomenclature being now admitted by every lover of chemistry, I shall make no apology for suggesting what I consider an improvement. The metalline salts are named after a plan which is extremely defective. It proceeds upon the supposion that no more than two oxides of any metal can combine with the same acid. The salt whose base is the first of these oxides is named as if there were no oxide present: thus, the protoxide of iron and sulphuric acid form what is called. sulphate of iron. On the other hand, the salt which contains the second of these oxides is known by oxy being prefixed, as in the oxy-sulphate of iron.

This mode of nomenclature is objectionable on several

accounts.

1st. It is extremely deficient in the extent of application,

as

as it makes not the least provision for those metals which combine with three and four proportions of oxygen; consequently there are no names for those salts which contain oxides intermediate between the minimum and the maximum. For instance, late experiments have shown that no less than three oxides of iron combine with the sulphuric acid. The first of these combinations is called sulphate of iron, the last is called oxy-sulphate; and for the second there is no chemical name.

2dly. It is evident that great confusion must arise from the want of some distinction between a superfluity of oxygen in the acid, and a maximum in the basc. Am I to suppose that the oxy-prussiate of iron is the peroxide combined with prussic acid ;—or must I conclude that it is the metal in an inferior degree of oxidation combined with oxy-prussic acid? Indeed, by pursuing the present nomenclature, we may soon expect to hear of oxy-oxy-prussiates and oxy-hyper-oxy-muriates, when there are at the same time an excess of oxygen in the acid and a maximum in the base.

3dly. When any metal has more oxides than two, the present nomenclature leaves us totally unable to distinguish the particular oxide united to the acid. Thus any one would suppose that the nitrate, sulphate and hyperoxymuriate of lead, each contained the same oxide base; yet we find these salts severally containing the prot-, deut-, and per-oxides. In short, to these capital defects in nomenclature Lascribe the slow progress which has hitherto been made in our knowledge of the metallic salts, and conclude that some improvement is absolutely necessary. That which I would suggest has at least the advantage of clearness and simplicity. I would carry into the nomenclature of these salts, Doctor Thomson's mode of designating the metallic oxides. For nitrate of lead, I would say nitrated protoxide, of lead; and for oxy-nitrate, I would say (if such salts can be formed) nitrated deutoxide, tritoxide, or peroxide, according to the degree in which the metal may happen to be, oxided. By this change every possible variety of these salts is provided with a name, clearly distinguishing the degree to which the Vol. 30. No. 120. May 1808.

X

base

base is oxided, and totally free from all the obscurity of the method now in use. Yours,

E. B.

P. S. As Mr. Davy's late experiments hold out to us the prospect of decomposing several substances hitherto ranked with simple bodies, I would beg leave to suggest the propriety of adopting names for them as nearly as possible allied to the nomenclature in use. I would call the base of the muriatic acid, muria; that of the boracic, borax; and that of the fluoric, fluor. We should not object to these words, that they will be unmeaning in their new application, and that some of them have been used before to signify other substances. We should recollect that words are only the signs of things, and possess no other relation to them than that which is derived from custom: we should also remem、 ber, that the words borax and fluor, though formerly used, are no longer chemical terms, and may therefore without impropriety be applied to any new substance. Upon this principle, I have always lamented that the base of nitric acid was not called nitre, instead of azote or nitrogen; for, if the acid were named regularly after either of these, it would be the azotic or nitrogenic, and not the nitric, acid.

LXI. Account of the Manufactures carried on at Bangalore, and the Processes employed by the Natives in Dyeing Silk and Cotton.

[Concluded from p. 272)

THE weavers of Bangalore seem to me to be a very ingenious class of men, and, with encouragement, to be capable of making very rich, fine, elegant cloths of any kind that may be in demand: but, having been chiefly accustomed to work goods for the use of the court at Seringapatam, they must now labour under great disadvantages; for it never can be expected that the court of Mysore should equal that of Seringapatam, nor will the English officers ever demand the native goods so much as the Mussulman sirdars did. The manufacturers of this place can never, therefore, be expected to equal what they were in Hyder's

6

reign,

reign, unless some foreign market can be found for the goods. Purnea, very desirous of the re-establishment of this city, has forwarded by me the musters of cotton and silk cloth that accompany this account, with a request that they may be presented in his name to the marquis Wellesley and I beg leave to recommend, that the attention of the board of trade may be directed to them, with a view of forming some commercial arrangements that may assist in restoring a country which has suffered so much.

ance.

The silk manufacture seems especially favourable for a country so far from the sea and from navigable rivers; as long carriage, on such a valuable article, is of little importAt present all the raw material is imported: but I see no reason why it might not be raised in Mysore to great advantage. Tippoo had commenced a trial; but, his arbitrary measures were little calculated to ensure success. Some of the mulberry-trees, however, that remain in his gardens show how well the plant agrees with this climate. It is true, that the experiments hitherto tried below the Ghauts have not been favourable: but much resolution and patience are always required to introduce any new article of cultivation; and I suspect that the climate here, owing to its being more temperate, will be found more favourable than that of the lower Carnatic..

There is a small duty levied here on every loom; and it is judiciously diminished to those who keep many, in order to encourage men of wealth to employ their capital in that way. A man who has one loom pays, annually, 3 fanams (2s. 6d.); two looms pay 5 fanams (3s. 44d.); and a man who keeps more than two looms pays only for each two funams, or 1s. 4d. All shopkeepers pay similar trifling duties.

There is here a set of people called Rungaru, who act as tailors, cloth printers, and dyers. Their printed cloths are very coarse, and the art among them is in a very imperfect state. The only two colours that they can give in printing are red and black. Their process is as follows:

The cloth that is to be printed is kept all night in a mix