The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1857-11-05

NEW CoMpAss.-We have had the plea
sure of examining a new compass, invented by
Mr. JAMES NJ. LILLEY of Greenville, Augusta county
and incline TO the opinion that it will receive the
approval of scientific gentlemen, when properly
understood. The instrument Is now on exhibition
at the Mechanics Fair, where all who feel interest
ed in such improvements should call ana see it,
The following description may serve to show its
use. as well as its manner Of operation:
''The seini-crcie represents doubic sseGmetrical
or trigunomctrica table. numbered rom the
of the diameter To the periphery, q ], B. 81,
g. IL, both ways, ami ai.o ffvtn te ehis oi te di,il
able limb on which the sights are liked, Is placed
over the table and rotates or traverses the sae from
s,lr end of the dia2feter, ami htving verneir TN
either end passing over The graduated edge of the
sen!i-circle, any cour3s angie can be readily OBJ
.ainei. by counting from the Moth or south end .i
te semi circla on the graduated edge dlyld. int
half degrees from up 20 go Theeige Of the move
able limb has scale coinc ding with the scale tie
table and numbered from the same point or center
of the tahi- both ways from o tt 10 Tue sights O.,
the undersie Of the plate coincide with the dam
tnr OF the semi-circis and noveabe limb When
nlsce,i AT a. aud IN lieu OF sights L sscopes can bt
attached by the same me sD5, when preferred by is
operator The moyeahie i'ne by tt.e Ore f the cen
Ger screw on the under side # tr plate can be tight
ened and kept sny required ptsiri0n AID tn u
ter pont be designated on the ground by plii-
met from the screw. HI. plate can he placed III
yer ical sitien. by means OF the iaii aud sp kei,
the socket having notch I'erntfiuS the 81 IN ;u
fall therein, whetcby anSiss Of rien atn or deprs-
son IN be a. en- iy ttker as HORIZONTAL an. So
The needle-hox aud evci placed parallel itb Ia,
sa M tee the ,efniercfc. b" taJlse, the 70
able iib the ~Taall re, and bsss lin" Of the tasie
ali of Which are laid G on the sam. s,ie, with re
small quadrant inItniel 30 iaciitiate the cars
lsnon " oblgpe anshd trigononittryi ana hnain2
the area Of trangies, For exHmpIa; The line the
aaoSeahe limb s, poles. tbs R. on the he u tbs
table 20 peles ai. the angle at the center # the
and the other two angles By setting th movable
limb to Geo on tbe verge Of The sefriefcie, ans
placing the noaider es the small bnb or rule ST NJ
Oh the movable limb, and moving the outer-enl %
The small rne until 1t eursse on the bss a the ibi
Will give the stance - On tie small 3ie a;i'i tl
sna;l gu.dranf viii give am ai,gloes 'c. wic.. VI
he angie given, being together taken frs.s y. p
caves the repianng angle eanat 10 or aud tkf &Sa
can be obsaincl ~ tracing tbs line 9" the table :
ihe yertex OF the ANGLO, tolmed by the two inH-,
The crcied edge Of the tabe, Will give the length -
the rerpendieti,ar tsthe base; tc half OF which b
lug mnltipliea by the base e'vss the "fe. ann y.
mede of ascertainipg the correct hafzuntal sn ~
n,ent in praeticai snrye. iag, and one or which IL j.
peculiarly adapted, Is I'll following: Place the piase
Ia a yertica po ition with the diameter eoncidine
with the a6ffsted leyet on the edge arf'tnge the
uioveahie limb 20 the slope Of fhr surftee which
verge Of the semcircle and whatever distance niea
sured along the slore. being tail on the movable
point the base line oi the table will rire the her
gontal distance from the center 81 the falle. assss
be perrendculsr and where nsr" ihaa on siess
tion or depression occurs the same line the 81
the seyerxi differences TAX from the whole length
O; the line will have the herizontsl measures
As the small quadrant eaa b. nIr,4~f eithef waF .ft
will give any angle lss Than lsoo at the ssltt al
pnint Of a tra1gie on the table IA
8. fssi UNI Mt will caculst the rsfio Of tire
needle tapprexlmatelh) by laying down on tne bass
line Of IN table the dstance run and the distance
piars the movable limb at the end 81 -ai distance
the perpendicular VIII give the vafisfion nn ti
verge Of the table. For instance. lay dswa . > q
the base, and the perpendicular poles atu "
will by placing the movable limb To the point on the
perpendieulsr, give 8 degrees on the verge Of the
.rns,e are other u.e. which we might tes ribs :