Table of 109 Leap Years, in a Cycle of 450 Years commencing with the Year 1800.

All these are Leap Years. In the plain numbers, or those without an asterisk, February has 29 days.

All those marked with an asterisk are double leap years, February has 30 days.

The last year has two asterisks, and February has 31 days, making 109 intercalary days in the whole, and completing the cycle of 450 years. The civil and the solar year ending at the same instant,

The first period of 900 years is calculated to correct the Julian and Gregorian calendar, and which correction is absolutely necessary; but the second period of 450 years is a far more elegant division of time, has the advantage of greater simplicity, would more readily meet the comprehension of the world at large, and might with great propriety be substituted for both.

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To the Editor of the London Journal, &c.

SIR,

A CERTAIN Hotspur who, though making free with my name, conceals his own, has attacked my labours and character, in terms which the simple love of truth could not have inspired! That love supposes a patient examination of the subjects treated of: and to such attention W. D. appears a stranger. To avoid the fatigue of thought, he consults an awkward experiment, which by the by, confirms my statements, and destroys his own! If, Sir, the readers of your Number for July please to look at W. D.'s Letter (page 25, No. XLIII,), they will see how lavish he is of reproof, how sparing of knowledge, and how careless of truth! He seems, indeed, to have equip ped his Pegasus, as Hudibras did his bony steed—so as to be goaded on one flank only

"As wisely knowing, could he stir

To active trot, one side of 's horse,
Travel worse."

The other would not,

In truth, W. D has made a foul blow at my talent and probity, on the flimsy foundation of his own. He has chosen a part of my work intended to elucidate a principle, and conjured it into a lamp! For I had taken care to inform my readers, that the fifth figure was only intended to explain how the oil in the higher tube, is supported by the united weights of the shorter columns below. (See plate 35, figure 5, of my Century of Inventions.) I therefore merely said, in that place," the oil will abide in the high tube, at A, as long as the mouth g is kept full, or nearly so." Indeed W. D. quotes these words, (but with a false emphasis,) in page 27, and his experiment proves their truth, almost as much as though

But if this bad

it had been made by an impartial man. been the case his syphon would have been applied, not at A but at g, and some of the oil have been drawn off there! when the oil in the longer tube, would not have remained at A, but have sunk to some lower level; where the burner of a lamp might have been placed. And if, afterwards, the oil previously taken away had been restored to the cup g, the surface at A would have again risen to its present level, so as for a time to supply a burner.

But in following W. D., I fall into trivialities. This tube is not the lamp I described, and if any of my readers find not a principle of elevation for the oil, I am content to pass for the dolt W. D. has attempted to make me! I will throw my descriptions behind the fire;" I will give up my "said-to-be-lamp;" I will abandon my "anomalous projects," and my "self-evident absurdities," to W. D.'s vapid censure, and submit to rank even below him in the scale of candour and science.

The lamp itself is given in fig. 6 of my 35th plate, which W. D. might have seen, at an inch distance from that fig. 5, he has so indiscreetly handled. Could it be that W. D. is afflicted with natural cecity? or was he wilfully blind to this figure, that he might have something to cavil at? However that be, my description says, "this lamp is seen to consist of a series of air tight cups embracing each other, one half with their mouths opening upwards, and the other half with their's opening downwards. (See pp. 278-9.) These inverted cups make one body with the moveable cover shewn between d and e; to which is soldered the tube h i, which sliding in the caseƒg, keeps this inverted vessel steady. We finally take notice of the weight placed under fg, upon the

said inverted vessel, and which helps to counterpoise the oil in the rising tube, &c."

Now, Sir, I ask any child of reason, whether this moving cover and its weight f g, do not actively press on the oil in the cups, and tend to urge it upward, and to raise new oil from the central cup below, to supply the consumption above? If I thought W. D. not incurable, I would recommend his trying another experiment to prove the fact; but more complete than the one be has made the ground of his present satire. Especially I would advise him not to strew so thick about him his broken darts, and to pause before he wounds the feelings of older, and mayhap wiser men than himself; and in general, I would counsel him (as they say the late king of Prussia did a too aspiring cadet) to "tarry at Jericho till his beard was grown."

To conclude, Sir, I trust my labours are already placed beyond the reach of such unfledged criticism as this and I expect you will give to my defence the same publicity as you did to W. D.'s unfeeling and unprovoked attack. This only will satisfy the lovers of truth, and secure the ends of justice."-I am, Sir,

Your obedient Servant,

JAMES WHITE, Civil Engineer.

Manchester, July 20th, 1824.

American Patent Laws.

OUR notice (at p. 35, of the present volume,) of some alterations in the Patent Laws of the United States, have called forth many enquiries among our readers, as to the fact of those alterations having actually taken place; we can only

say, that the information was given as we received it from Washington, and we are unable to satisfy the doubts of our enquirers, until we obtain answers to our letters from America, which will necessarily occupy several months.

It is certain that a patent has been obtained in the United States, by an Englishman, Mr. Brown, for the invention of a certain improved Engine, (the same described in our present number,) he never having resided in that country; but whether an Act of Congress, passed expressly for this individual case, may have given rise to the supposition that the general laws of patents have actually been revised and altered, we cannot at present determine. The American Consul has not yet received official intimation of the change, though he is not prepared to deny it, as such a project has been for some time past in agitation, and without doubt will shortly (if not already enacted) be carried into effect in that country.

Novel Enventions.

Bleaching Flax and Hemp.

A

AFTER the flax or hemp has been broken from the boon, and otherwise cleansed from its woody particles, it is to be tied in bundles, by a cord passing round its middle; if the staple is very long it may be tied in bundles of about one pound, but in general a smaller quantity will suit better. These bundles are to be immersed in a solution of slaked lime, of the consistence of whitewash, for about six hours, after which they are to be washed in clean water, so as to discharge all the lime from the fibres; it is then to be boiled