. 
of the Pantograph. 403 
to any particular instrument, the number on it must be multi- 
plied by the actual value of 2d. 
Such is the facility and extension given to a pantograph when 
graduated as above described, that I would recommend the pos- 
sessors of well-made instruments which are defective in this re- 
spect, to have the scales properly Jaid down upon them. But 
if they do not choose to he at that expense, they may avail them- 
selves of the formule and table here given, to lay down marks 
on their bars as occasion may require ; and in such case it would 
be a preferable mode, instead of the tabular value, to take their 
complements to 0-5, and to set off the distances from the lower- 
most division on the instrument, which is marked 1. 
ar.) 
7 is applicable to 
pteae 
It may be remarked, that the expression a 
the graduation of the proportional compasses, 2d being the en- 
tire length of the instrument. The distance between the centre 
of the joint and the index mark is to be added, as a constant 
quantity‘to all the values. lam, &c. 
Lewes, April 16, 1822. J. W. WooLLear. 
Scale A. 
Scale A. Scale B. 
Div. Long B. Short B.{ Div. Long B./Short B.i Div. Long B.|Short B. 
mak ical ia fd i 
100 | 0°50 | 0:5000 } 67 | 0°335 | 0°4012 | 40 |0°3333 | 0-40 
99 ‘495 | 4975 | 66 | <°33 3976 4 39 | °3197 ‘é 
98 “49 "A949 | 65 | +325 3939 | 38 | *3065 |] -38 
97 | ‘A85 | 4924} 64 -32 3902.1 37 | -2937 | -37 
96 "48 4898 | 63! °315 3805 § 36 | ‘2812 | -36 
95 ‘475 | ‘4872 1 62 | -31 | -3827 135 | -2692 35 
94) “47 | 4845161 | -305 | -3780 | 34] -2576] -34 
93 | 465 | -4819 | 60) -30 | -3750 | 33 | +2463) -33 
92 “46 4792 5 59 | +295 “3711 32) °2353 G2 
91 | *455 | 4764458 | -29 3671 f Sl | 2246] -31 
90° °45 | 4737157, -285 | +3631 | 30 | -2143 |- -30 
89 | -445 | -4709 | 56) -28 3590 | 29 | 2042 | -29 
88 | 44 | 4681155 -275 | 3548] 28 | “1944 | -28 
87 | -435 | 4652154] -2 "3506 | 27 | °1849 | -27 
86 | 43 | 4624} 53| -265 | -3464[ 26 | -1756| -26 
85 | 425 | 4595452 | -20 | -3421 | 25 | 1607} -25 
84 | -42 | 4505) 51) -255 | 3377) 24 | “1579 | 2 
83 | 415 | 4536450] -25 | -3333 4 23 | 1494] -23 
82] -41 “4505 22} +1410 | +22 
81 | “405 | +4475 Scale B. 21] +1329 2) 
80} -40 | 4444 | —--————-———] 20 | 1250 | -20 
79 | -395 | -4413 |Div.|LongB.|Short B| 19 | -1173 | -19 
78 | -39 | -4382 } -—- ~ -{ 18 | -1098 | +18 
77| °385 | *4350 | 50 | 0-500 | 0:50 17 | -1024 | 17 
76 | °38 ‘4318 | 49 | -4804 | +49 16 | ‘0952 | +16 
75 | °375 | ‘4286 | 48 | °4615 | °48 15 | 0882 | -15 
74 1, "4253 | 47 | *4434 | °47 i 14 } -0814 “14 
73 | *365 | 4220 | 46 259 | °46 3:1) 0747) 313 
72 | +36 “4186 } 45 | -4091 | °45 | 12 | 0682 | <12 
71 | 355 | °4152 | 44 3929 | *44 11} 0618 | *11 
70 | +35 ‘4118 } 43 | 3772 | +43. $10] -0556]>-10 
69 | ‘345 | +4083 } 42] °3621 “42 | 9 | 0495 | +09 
63 34. «| +4048 4 4) | +3475 | -Al 8 | 0935 | -08 
