1804 to Dr. Thomas Thomson, the very learned professor of chemistry in the University of Glasgow, and by him they were inserted in his system of chemistry.. But it was not a truth that could electrify the world, it was on a subject on which few thought, one of which many said, "what is the use of it?" that miserable question which occurs to men to whom the revelation of God's truth is of no interest, unless an immediate advantage is promised. Dr. Thomson (Nicholson's Journal, Vol. 21, p. 87) says even four years after, "This curious theory, which promises to throw an unexpected light on the obscurest parts of chemistry, belongs to Mr. Dalton;" shewing that even then it required to be taught even to chemists. We find in reality that for years afterwards it was to most chemists a mere speculation.

In a paper by Wollaston in the same volume, p. 164, he says, "Dr. Thomson has remarked that oxalic acid unites to strontian as well as to potash in two different proportions, and that the quantity of acid combined with each of these bases in their superoxalates is just double of that which is saturated by the same quantity of base in their neutral compounds. As I had observed the same law to prevail in various other instances of superacid and subacid salts, I thought it not unlikely that this law might obtain generally in such compounds, and it was my design to have pursued the subject with the hope of discovering the cause, to which so regular a relation might be ascribed.

"But since the publication of Mr. Dalton's theory of chemical combination, as explained and illustrated by Dr. Thomson, the inquiry which I had designed appears to be superfluous, as all the facts that I had observed are but particular instances of the more general observations of Mr. Dalton, that in all cases the simple elements of bodies are disposed to unite atom to atom singly, or if either is in excess, it exceeds by a ratio to be expressed by some simple multiple of the number of its atoms."

It is plain that Wollaston, who was behind in no theories, was unable to obtain from the knowledge of the times an explanation of these phenomena, even when he saw the difficulty clearly; and it is plain also, that although it was said that he would have discovered it had Dalton failed, that he did not discover it even when he had in his hands as many facts as Dalton had, and a greater power of accurate workmanship. The genius was wanting, the acuteness of Wollaston and of Proust could not penetrate, where the simplicity of Dalton was at home.

In Sir Humphrey Davy's Bakerian lecture for 1809, in giving some analyses, he says, "the same proportions would follow from an application of Mr. Dalton's ingenious supposition," but even he, with a mind much more capable, as we might suppose, of delighting in grand general laws, such as from their brilliancy come upon us like the finest poetry, even then saw little in the new theory, and said little upon it. When it began to be established he was inclined to prove that Dalton was not the first discoverer, although when he delivered his discourse on giving Dalton the gold medal of the Royal Society he had arrived at a clearer view of the subject. The same slow vision was, as might be more readily conceived, the case with Berzelius, who took it gradually up as it came from his own analyses, growing during his whole life into more and more absolute certainty. But Dalton had given a table of atomic weights in 1803, and for years these philosophers plodded after him with numberless proofs, Berzelius surpassing all others in accumulating and arranging scientific wealth.

It will not be pleasant to review the delinquencies of our great men, nor the slowness of their conceptions, their desire to limit the law, and to cramp it down to the bounds of their own knowledge, denying its power to explain more than they had seen. Scepticism has its work to do in the world, and credulity has had many victims, but it may well be said that the amount of knowledge to be gained is so great that our

capacities for belief must enlarge themselves rather than diminish, and we shall be left behind with a small and inadequate supply of intellectual food, if we refuse to take it until we have extracted its one-tenth per cent. of questionable adulteration.

The law has established itself; it is true. Our knowledge of its ramifications will increase. If it had not great ramifications, we might question its own intrinsic greatness. Isomorphism and isomerism are two of these, beautiful in every respect, thoroughly beautiful. But they are no contradictions, the number of provinces do not prove the smallness but the greatness of a kingdom. Why then should they even be mentioned as modifications, they may be said even to be necessary results.

Allotropy is itself a curious and beautiful fact, and, one that we may readily suppose will widen itself out, perhaps even till alchemy itself shall cease to be wonderful; but it does not disprove the atomic combinations.

We may call the ultimate particles which practically unite equivalents, as Wollaston did, but we don't alter the fact, we only chronicle our hesitation, and substitute a name which cannot be final, as it represents only a temporary theory; it only says that the quantities are equivalent to each other, but refuses to decide what these quantities are. We may call them volumes, like Berzelius, but we find then that we go on a wrong hypothesis, as the atomic volumes are not the same as their weights in every condition, whatever might be the case if all were gaseous.

We have, in fact, found no name representing the case as well as atom, and, giving due limits to the meaning of the word, it represents the state of belief in the mind of every chemist, whilst no fact whatever bears directly against it.

At the same time I do not mean to advocate the atom with the physical constitution given to it by Dalton, as well as by Newton and the ancients, not being able to see it possible;

but this is not a place for my own views: I have referred to what may be called the practical atom, or the smallest amount that unites.

Is then chemistry scientifically disposed of by this theory? as well might we say that Newton exhausted the heavens of its knowledge. Year after year will furnish us with marvellous truths, nor can we believe that centuries or millenaries will exhaust God's wisdom in the earth. Already has Davy's aluminum, a brittle useless powder not quite pure, turned a beautiful metal, and the slippery mud of a clayey soil been assimilated to "shining silver." The atomic theory may be further analyzed, and under its simple laws may be found another which will not only include all we now have, but a host of others still unsuspected; the time may even come when a new chemistry will be revealed to us, a world under our present elements, when every element will be convulsed and shaken into fragments, by powers which nature will put into our hands; but even that does not destroy the laws of the present. Even when that scientific convulsion comes, we can scarcely doubt that the elements will break up, well proportioned and according to regular laws, if they break into fragments at all. But this stratum of our knowledge cannot be annihilated by any under stratum; what we have found is true, whatever higher truths may overpower us with their splendour. When these truths come let us receive them openly and willingly, giving them encouragement instead of envious repulsion, knowing, in fact, that they must come, and rather let us make an occasional mistake in harbouring a mere mortal, than lose the opportunity of an angel for a guest. There are incredulous fools who have made the world's throbbing heart a blank to them, lest they should perhance at times be cheated. There have been madmen who have refused to eat, lest they should be poisoned. • These reflections naturally arise on considering the manner in which Dalton's discovery was reviewed. It cannot be denied, however, that the time being nearly ripe was the

cause of its ultimate success.

To discover out of place and

out of time is a great misfortune. To be before the age in knowledge is to a man a curse, and to a generation no advantage; at least it would seem so, although there may be a value even for this occasional misplacement not to be lost sight of in estimating man's progress towards a higher civilization. But in such cases the individual is not appreciated, the generation does not hear him, his years pass by in misery, and his attempts to teach are a failure. That knowledge is best rewarded which is a fit evolution of the age, and which can be at once put to use for practical purposes, or for mental cultivation. It behoves us then to be respectful towards new opinions, and tender towards crotchets, lest we may be laughing, as so many have done before us, at beautiful truths. The rudiments of truth are no more beautiful to us than the roots of flowers, until we study them thoroughly; by forgetting this men are made victims who ought to be revered.