This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...and were plotted upon the same sheet. In Fig. 35, to which reference has just been made, the unbroken line represents the changes in the position of the declination needle as recorded at Washington on the day in question. The two broken curves are those obtained by making readings with the two galvanometers in the ...
Read More
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...and were plotted upon the same sheet. In Fig. 35, to which reference has just been made, the unbroken line represents the changes in the position of the declination needle as recorded at Washington on the day in question. The two broken curves are those obtained by making readings with the two galvanometers in the laboratory at Ithaca. It will be seen that the three curves agree in a remarkable manner throughout. The consideration of these results makes it obvious that in order to use a sensitive galvanometer in operations of precision, two things are necessary: FIG. 35. 1. A knowledge of Jfin the locality where the instrument is in use at the time when calibration of the latter is made. 2. Some method of following the fluctuations of H from moment to moment. A discussion of the means of meeting this second requirement will be given in a subsequent lecture. The methods of determining H, described in the fourth lecture are very laborious, and it is desirable, therefore, to substitute for them some means for comparing the strength of unknown fields with that of known fields previously'determined for this purpose the method of Wilhelm Weber is most convenient. It is described below. Weber's Method for the Determination of H.--The procedure consists in turning a coil of known dimensions (the earth inductor) suddenly through 180, and noting the throw of the slow moving needle of a ballistic galganometer placed in circuit with this coil. Fig. 36 shows the instrument in its simplest form, while Fig. 37 gives the arrangement of the electrical circuit. The earth inductor is a coil of considerable area, and consisting of many turns of copper wire. The dimensions of the coil, the number of turns and the resistance of the instrument will depend upon the character of th...
Read Less
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
New. Trade paperback (US). Glued binding. 120 p. In Stock. 100% Money Back Guarantee. Brand New, Perfect Condition, allow 4-14 business days for standard shipping. To Alaska, Hawaii, U.S. protectorate, P.O. box, and APO/FPO addresses allow 4-28 business days for Standard shipping. No expedited shipping. All orders placed with expedited shipping will be cancelled. Over 3, 000, 000 happy customers.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
Fine. Trade paperback (US). Glued binding. 120 p. In Stock. 100% Money Back Guarantee. Brand New, Perfect Condition, allow 4-14 business days for standard shipping. To Alaska, Hawaii, U.S. protectorate, P.O. box, and APO/FPO addresses allow 4-28 business days for Standard shipping. No expedited shipping. All orders placed with expedited shipping will be cancelled. Over 3, 000, 000 happy customers.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
New. Trade paperback (US). Glued binding. 120 p. In Stock. 100% Money Back Guarantee. Brand New, Perfect Condition, allow 4-14 business days for standard shipping. To Alaska, Hawaii, U.S. protectorate, P.O. box, and APO/FPO addresses allow 4-28 business days for Standard shipping. No expedited shipping. All orders placed with expedited shipping will be cancelled. Over 3, 000, 000 happy customers.
