Agricultural Students Gazette (Google eBook)

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Page 130 - ... building. If the mill were then struck with lightning, it would remain charged for some time, and a person standing on the ground outside and touching the wall might receive a shock, but no electrical effect would be perceived inside, even on the most delicate electrometer. The potential of everything inside with respect to the earth would be suddenly raised or lowered as the case might be ; but electric potential is not a physical condition, but only a mathematical conception, so that no physical...
Page 130 - ... the inside of a gunpowder manufactory. If this is clearly laid down as our object, the method of securing it is equally clear. An electric discharge cannot occur between two bodies unless the difference of their potentials is sufficiently great compared with the distance between them. If, therefore, we can keep the potentials of all bodies within a certain region equal or nearly equal, no discharge will take place between them.
Page 131 - ... with the conductor would render the telegraph useless, no telegraph from without should be allowed to enter a powder-mill, though there may be electric bells and other telegraphic apparatus entirely within the building.
Page 131 - ... powder-mill it might be advisable to make the network closer by carrying one or two additional wires over the roof and down the walls to the wire at the foundation. If there are water or gaspipes which enter the building from without, these must be connected with the system of conducting-wires, but if there are no such metallic connections with distant points, it is not necessary to take any pains to facilitate the escape of the electricity into the earth. Still less is it advisable to erect...
Page 6 - Carboniferous limestones, observed to have presented a marked even surface, viewed on the large scale, for the deposit of the former, but, throughout, this surface has been drilled into holes by lithodomous animals, which must have existed in the seas at the commencement of the Inferior Oolite. The holes which were observed by Professor John Phillips, in 1829, are of two kinds, one long, slender, and often sinuous, extending several inches into the Carboniferous limestone, the other entering that...
Page 130 - ... if it had not been erected ; but each of these discharges will be smaller than those which would have occurred without the conductor. It is probable, also, that fewer discharges will occur in the region surrounding the conductor. It appears to me that these arrangements are calculated rather for the benefit of the surrounding country and for the relief of clouds labouring under an accumulation of electricity, than for the protection of the building on which the conductor is erected.
Page 130 - We might even place a layer of asphalt between the copper floor and the ground, so as to insulate the building. If the mill were then struck with lightning, it would remain charged for some time, and a person standing on the ground outside and touching the wall might receive a shock ; but no electrical effect would be perceived inside, even on the most delicate electrometer.
Page 131 - ... rainwater pipes. In the case of a powder-mill it might be advisable to make the network closer by carrying one or two additional wires over the roof and down the walls to the wire at the foundation.
Page 61 - It is certainly unadvisable, in the present state of prices of agricultural produce and labour, to break up any tolerably good pastures for the purpose of converting them into arable land.
Page 37 - food " shall include every article used for food or drink by man, other than drugs or water, and any article which ordinarily enters into or is used in the composition or preparation of human food ; and shall also include flavouring matters and condiments.

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