SECTION YI.

MISCELLANEOUS SCIENTIFIC INVESTIGATIONS. BY W. STURGEON.

An Investigation on the cause of the Fracture of Jars during an Electric Discharge ;and on the mode of protecting them.

Perhaps no circumstance whatever tends more to damp the spirit of philosophicalinquiry, or retard the progress of scientific pursuits, than that of expensive apparatus,and the liability of spoiling various parts of it by the process of experiment, withoutever attaining anything like a satisfactory result. Experiments are frequentlyattempted, both in Chemistry and Electricity, which, if unattended by misfortune,might lead to the most important results ; but the breaking of a retort or a jar in onemoment defeats the object, and the Experimenter, by this unfortunate circumstance,abandons perhaps altogether the subject he was ardently pursuing. Any attemptthen, however humble, that can possibly aleviate the embarrassment of the Experi-menter under such painful and discouraging circumstances, must necessarily beconsidered of some importance, not only in any particular inquiry, but to the encour-agement of scientific pursuits in general.

Electric jars, when charged intensely, it is well known are frequently preforated,or starred, as some persons call it, on being discharged. Many Experimenters breaktheir jars by the unscientific practice of placing one of the balls of the discharging-rod against the side on the coating, whilst the other ball is made to approach thatof the jar, and which communicates with the lining. For, with this disposition of thedischarging-rod, it is evident that when the discharge takes place the whole force ofthe concentrated fluid, which before was distributed over the whole area of the lin-ing, is now suddenly impressed on that particular point of the coating immediately incontact with the lower ball of the discharging-rod, and the glass not being sufficientlystrong to sustain the shock is frequently perforated, and then (as to electrical pur-poses) rendered entirely useless.