Intelligence and Miscellaneous Articles. 415 



on the double difference of the two velocities. With a plumbline 

 of only 10 feet length, Gruithuisen made some observations which 

 (I. c. p. 33) had been related in his work entitled " Lieblingsobjecte 

 anf dem Eelde der JNaturf orschung " (Munich, 1817), pp. 69 etseq., 

 26, 77, 128. I have not been able to procure a sight of this work. 

 In the Analehten, I. c. pp. 33, 34, it says of these observations : — 

 "In my very first experiments it proved that this instrument 

 (w T hich I named ellcysmometer) exhibits effects ivhicfi depend not on 

 accidental causes, but on the actions of the gravity and motion of the 

 earth and the increasing nearness of other large heavenly bodies, which 

 latter would announce themselves through the plummets so posi- 

 tively and distinctly, even if we had no ebb and flood. The eastern 

 deviation of the elkysmometer-thread was most striking from 8 to 



9 o'clock in the morning It was also unmistakable that the 



moon exerted an attraction on the elkysmometer, especially in the 

 morning, when she was just between the sun and the earth." Also 

 the elkysmometer indicated to him "earthquakes, even from other 

 parts of the world" (I. c. p. 34); and on p. 37 the superiority of 

 long plumblines to short ones is demonstrated in detail ; indeed a 

 table is given at the end for the reduction of very small sines to arcs 

 for the sake of observations on very long elkysmometers. 



With the rough arrangements described, there is no doubt that 

 Grruithuisen's results depended on accidental external disturbances, 

 and perhaps in part on illusion, as a short calculation is sufficient to 

 show that, here, plummets would scarcely ever lead to any result- 

 Only the name proposed by him (eAKv^yua = traction, eXicw— I draw), 

 though it is not correctly formed and should have been " helko- 

 meter," deserves to be adopted. 



But the most remarkable thing comes last. In his Neuen Ana- 

 lekten fur Erd- iind HimmelsJcunde, Band i. Heft 1, published at 

 Munich in 1832 (finished, according to p. 72, "am 27 Juli 1832"), 

 pp. 39 & 40, there is a memoir entitled, " Bitter Bessel's Experi- 

 ments on the Force with which the Earth attracts bodies of various 

 natures, and of the Editor's Elkysmometer and Hengeller's Swing 

 Balance." 



After a report, occup}T.ng only 19 lines, on Bessel's pendulum- 

 experiments with gold, silver, lead, iron, zinc, brass, marble, clay, 

 quartz, water, meteoric iron, and meteoric stone, all of which gave, 

 to less than -g-oinro' the same length for the simple seconds-pendu- 

 lum, it says verbatim* : — 



" By these experiments one of my most anxious wishes is ful- 

 filled. Already twenty years since (in 1812), I suspended on wires 

 of several fathoms length bodies of various natures, in order to try 

 whether the opposite positions of the moon towards them would 

 effect any deviation from the vertical line. But as the place was 

 not faultless for such experiments, I held that the results of the 

 experiments were not worth publishing. A pendulum of such a 

 length I called an elkysmometer when a scale to be read with a 



* The figure is a faithful fac-simile of the original. 



