bits, we may almost say the nature, of man is changed by time; one race of men succeeds another, empires rise upon the ruins of former kingdoms, enlightenment and science progress, and again decline. Look, too, at languages: how various! how imperfect! how changeable! How many have been swallowed up in the gulph of years, or descended to us entombed in a few ancient works! Does not this speak plainly of the instability, the corruption, the fall, the confusion of man? On the contrary, the race of animals, all destined to perish, while man is born for immortality, remain uniform in their generations, unmoved by the convulsions of the world, untouched by time; and the song of a bird which now fills the air is the very same which, six thousand years ago, the first of his species poured forth in homage when he came perfect from the hand of his Creator."

Thomas Thursfield, Esq., next read a very able paper on the Basaltic Dyke at Shatterford, and the vegetable remains in the adjacent coal measure. The paper displayed deep research and an intimate knowledge of the subject; and was illustrated by a drawing and many beautiful and valuable specimens.

On the motion of Mr. Aston, seconded by Mr. Cookes, a vote of thanks was given to the Rev. J. Pearson and Mr. Thursfield for their scientific and highly interesting papers; and the meeting broke up, highly gratified with the proceedings which had been laid before them.

SHROPSHIRE AND NORTH WALES NATURAL HISTORY AND ANTIQUARIAN SOCIETY.

THE session of this Society terminated on the 2nd of May, during which the following interesting lectures and valuable scientific papers have been read: January.-Lecture on Pneumatics, by Henry Johnson, M.D.; on the Conversion of Cast-Iron into Plumbago, by Thomas Du Gard, M.D., F.G.S.; a Continuation of the Shropshire Fauna, comprising a portion of the class Aves, by T. C. Eyton, Esq., F.L. and Z.S. February.-Lecture on the Affinities of Vertebrate Animals, by T. C. Eyton, Esq., F.L. and Z.S. March-Lecture on Electricity, by Mr. Thomas Blunt; on the Utility of Antiquarian Research as connected with the Remains of Shrewsbury Abbey, and recent discoveries therein, by Mr. Henry Pidgeon. April.-Lecture on Optics, by Henry Bloxam, Esq.; on a Deposit of Mammalian Remains on the Coast of Kent, communicated by the Rev. B. H. Kennedy, D.D. May.-Lecture on the Metamorphoses of Plants, by W. A. Leighton, Esq., B.A.; on the Composition of Soils, by the Rev. C. A. A. Lloyd, M.A.; on the Roses of Britain, by Edwin Lees, F.L.S.

Among the very numerous donations to the Museum and Library lately received, the following may be enumerated as the more valu

able:-Sixty-four Foreign Birds, from Mr. John Gould, F.Z.S.; Thirteen Silver Coins of Edward I., Edward II., and Alexander of Scotland, found in the bed of the river at Tutbury, Staffordshire, supposed to be part of the contents of the military chest of the Duke of Lancaster, when in retreat before Edward II., which was lost about that place, from C. C. Babington, Esq., F.L. and G.S.; a Collection of Fossils from the Chalk, &c., from C. C. Babington, Esq.; a large Collection of Roman and English Coins, from Sir A. V. Corbet, Bart.; African Pig, Doe and Fawn, numerous birds, crania, fresh-water shells, &c., from T. C. Eyton, Esq.; Historical Register, 14 vols. 8vo., from the Rev. Canon Newling; Collection of dried specimens of British Rose and Rubi from Edwin Lees, F.L.S., M.E.S.

CRITICAL NOTICES OF NEW PUBLICATIONS.

Reports on the Explosion of Steam Boilers, by a Committee of the Franklin Institute of Pennsylvania. Part I., containing the first Report of Experiments made by the Committee for the Treasury Department of the United States. Part II., containing the General Report of the Committee.

The Reports now before us, from a committee of the Franklin Institute of Pennsylvania, are upon a subject of special interest to every community where steam is extensively used as a motive power. They emanate from an institution which has been very active in the promotion of the mechanic arts in the United States of North Ame rica, and come to us with the sanction of a committee of its members, and of its board of managers. The names of most of the gentlemen composing the Committee have been more or less familiar to the readers of the Journal published by the Franklin Institute.†

• While this article was going through the press, the lamentable occurrence of an explosion of the boiler of a steamer at Hull renders it but too appropriate. The ignorance displayed before the coroner's inquest by those who were concerned in the management of the engine and boiler, shows plainly that light has not yet reached those in whose care our lives are so often placed.

+ Our cotemporary, the anonymous editor of the Magazine of Popular Science, should at least have given himself the trouble to look into the facts of the case, before he insinuated a doubt of the qualifications of these gentlemen for the task imposed by the Franklin Institute. A reviewer should bring both candour and knowledge to his task, and our cotemporary really seems to have been wanting in both. We refer to the Journal of the Frank lin Institute to show that seven of the members of the Committee, whose

On their appointment, in 1830, the Committee addressed letters to persons whom they supposed might furnish information in regard to the subject before them, and have published the replies in the same Journal in which their reports first appeared.* At the request of the Secretary of the Treasury of the United States, they also undertook two series of experiments; the first intended to test the truth of the various causes which have been assigned for the explosions of steam boilers, and the second to determine the strength of the materials commonly used in their construction. The first-named series of experiments being that upon which the general report of the Committee is based, was published+ next in order to the replies to their letters, and we were thus furnished with the means of judging, independently of the authority of the Committee, of the accuracy of the conclusions in their General Report. The second series of experiments is now in the course of publication.

We propose, in the following article, to give as full a view as the nature of our journal will admit of the General Report of this Committee, and of their experiments, inverting for this purpose the "inductive" order, and following the discussion of the causes of explosion as enumerated by the Committee, in their General Report, referring to the experiments as the subjects of them came under discussion.

1st. Explosions may occur from undue pressure within a boiler, the pressure being gradually increased.

It would seem that there could be no difference of opinion as to these being a "vera causa." Engineers have, however, alleged that boilers, particularly if made of copper, only rend by a gradually increased pressure, and thus discharge their contents without dangerous violence. A most dangerous maxim is stated, in this Report, to

works are under discussion, are, or were, Professors of Natural Philosophy or of Chemistry. Four other members we find, from the same source, to be practical mechanics. One other has written much on Mechanics. We are thus left in doubt as to the professions of but four, out of seventeen, of the Committee.

* Journal of the Franklin Institute, vols. viii., ix., x.

+ Journal of the Franklin Institute, vol. xvii., and London Mechanics' Magazine. The first and second parts of this Report have been printed in a separate form by the Frankiin Institute, and kindly presented to several of our scientific societies.

Both series of experiments were made by sub-committees, whose names are given in the Preface to the Report. On neither of them do we find the name of Professor Hare, who is vauntingly said by our cotemporary before noticed, in his attempt to discredit this Report, to have "openly stated that he never attended a single experiment." We do not intend to fatigue our readers by following the disingenuous criticisms of our anonymous friend in detail, considering, as we do, his review to be discreditable to a journal professing to give information upon science. It is the more objectionable because interspersed with general epithets of approbation, which are totally misapplied if the individual criticisms are in the least warranted. Besides perversions of fact, we have, in his review, such language as this:"President Jackson and some of his fellow citizens down east ;"- "There must be a district in Pennsylvania where the shamrock is worn!" &c.

be prevalent among engineers on the western waters of the United States, that, provided a full supply of water is kept in a boiler, there is no danger of explosion from increasing the steam pressure.*

To set this question at rest, two cylinders-one of iron and one of copper-were partly filled with water and exposed over a fire, so as to increase the pressure of steam within; the greatest amount of this pressure, before the cylinder gave way, being registered by a spring

gauge. The material facts attending the bursting of the iron boiler are thus stated by the Committee :

* *

"The explosion tore off one of the heads, b c, of the cylinder, projecting the other parts of the boiler in an opposite direction, carrying with them, for a portion of the distance, the iron cylinder forming the furnace, and scattering the fuel in every direction. The boiler head was thrown fifteen feet, the boiler and spring register about six feet, and the furnace, weighing about forty-five pounds, was overturned and carried four feet. The pressure indicated by the register was 11 atmospheres. The circumstances of this experiment show that the steam rose quite gradually on account of leaks in the boiler, increasing, probably, more rapidly as the quantity of water diminished, the intensity of the fire, meanwhile, increasing; that, at a certain period, the tension within had attained about eleven atmospheres, when the boiler exploded violently."

*

"As before, nothing remarkable occurred previous to the instant of explosion, and the members of the committee employed in the experiments were engaged in observing the boiler at the instant it exploded. A dense cloud of smoke and flame, capped by steam, rose from the pit; the stones and combustibles were widely scattered, and the boiler was thrown, in a single mass, about fifteen feet from the furnace. The noise attending this explosion was like that from the firing of an eight inch mortar.

The boiler was rent as shown in the accompanying figure, giving way in an irregular line, just above the probable water-line on one side of the boiler, but not conforming to it. d and b were the lowest points in the two heads

This same opinion we see in the evidence of one of the parties examined before the coroner's inquest in relation to the late accident at Hull.

before the explosion. The sheet of copper was torn from the heads, un

rolled, and irregularly bent, adhering to the heads for only a short distance near the top of each; and the heads were bent outwards. The thickness of the copper along the line of rupture varies from 0.25 to 0.35 of an inch, and the metal appears to have been highly heated at one end of the torn portion."

To a gradual increase of pressure beyond that which the material of the boiler would bear, the Committee refer certain well-known accidents, which are upon record; as that in Wellclose Square, London, that of the steamer, Rhone, &c.

The safety-valve being the means commonly relied on to prevent a dangerous accumulation of steam within a boiler, the Committee thus enumerate the causes which may render it inoperative :-Design on the part of the engineer or attendant, and adhesion of the valve to its seat by rust or other cause. This adhesion, the Committee consider, cannot be traced to the peculiar phenomenon observed when a disk is placed before an aperture, whence a fluid is rapidly issuing. This phenomenon has been the subject of much examination. The first observation of it is claimed by M. Clement, of Paris, and by Mr. Roberts, of Manchester. Theory and experiment both shew it to depend upon the relative dimensions of the disk and aperture; and as these are not very unequal in the case of the safety-valve, the tendency of the disk towards the opening is inconsiderable. This deduction is further confirmed by the experiments of the Committee, who used a graduated safety-valve, and compared its indications of pressure with those of a mercurial gauge, or with those deduced from the observed temperature of the water in the boiler. Two different valves were used in different parts of the series of experiments, both