VI 



ART. PAGE 



2^). ^Miiliiiilifatioii and Ke';i>:tiy of Üw motion LS 



21. Miiltiplicatiiiii l)y au iii(k[)eiuk'Ut levcr lit 



'2'2. Kt'ciinl of successive tlL-iplaceuieuts in conjunction witli tlie time 20 



2."5. Acliml Horizontal Pcnduluni Scisinoirrapli 20 



24. ]in|irovfil Ibnn of Horizontal Pendulum Seisniogi-ai)li 22 



2ö. Horizontal Pendulum Sfisniourapii with King Bob 24 



2li. Ivchuiou of tlio Friction Kiicji- |o ilic dimensions of tlie frame aiul to 



tiie suspended mass 24 



27. Horizontal Pendulum with flexilile tic and pivottcd .strut 2(i 



2^. I[ofizontal Pendulum without jt)ints 27 



2!l. Hiirizoulal I'lnduluni with two 'dejj;ree.s of freedom 28 



CHAPTEPv HI. 



ormoi: iN.<ri:iMENrs k<>u oiweüvinc hoiuzontai, movkmen't. 



•^^^. ^[lu^ tree t.. roll 29 



151. lioilini; Sphere Seismoirrajih 30. 



.■{2. Friction in the liolling Sphere Seismometer 32 



33. Other Rolliu"; S])here Seismo<;raphs 33 



34. UoiliiiLT Cyliiidi r Scismourapli 34 



35. Tile ("onimoii Pendulum 35 



3(i. .Vetual Pendulum Seismometers 37 



37. Louir Pendulum Seismogra]'h 38 



3.S. hitlMence of friction on the Pendulum and other Scisniünulers 40 



3'.(. Slioit Pendulum with considerahle friction 41 



411. Mi'lhods ot' makinir a short peuiluhiMi aslalie 42 



41. I>u|'|i'x Pcuiluiiini Si'isiiioinrlcr 42 



42. DujiUx Pi ndtdum uilli a single l)oh 44 



43. Forhe.s' Inverted Pendulum Seismometer 4-") 



CHAPTER IV. 



ISSTKHMENTS rnl! dnsEKVIXC VEUTICAT. MOVEME.NT. 



44. Loaded Spiral Spring -^"i 



45. Hoiizontal Bai with Ihxihlv .-upport and loaded ind ... 47 

 111. Horizontal r>ar uilh stretched supporting spring and |oad(d end 4S 



47. Asiatic Horizontal Bar, without liijnid 4!) 



4H. .\clual Verlical-^Iotiou Seismogra]ili 50 



4!l. irvdrometer Verlieal-.Motion Seismograjih 51 



