Dr Graves on t?ie Seme of' Touch, 69 



ing scale as to the measurement of the limit qfconfusiouy was 

 taken from experiment on himself. He entitled it " Tabula 

 graduum subtilitatis tactus in potissimis corporis mei partibus, 

 quos per minimam distantiam crurum circini corpori impositorum, 

 qua perpendicularis et horizontalis crurum situs, et intervallum 

 interpositum sentiri poterat, metitus sum.^ The limit of confu- 

 sion in the following table is therefore the distance at which the 

 points of the compass could not only be perceived to be distinct 

 from each other, but their direction, whether horizontal or per- 

 pendicular, could be judged of. 



Tip of the tongue, ^ line. Inner surface of the ifinger tips, 

 1 line. Red part of lips, 2 lines. Inner surface of second pha- 

 lanx of fingers, 2 lines. Outer or third phalanx of do., 3 lines. 

 Top of nose, 3 lines. Inner side of extremities of metacarpal 

 bones, 3 lines. Dorsum of the tongue one inch from its point, 4 

 lines. The portion of the lips which is not red, 4 lines. Edge 

 of the tongue, one inch from its point, 4 lines. Metacarpal bone 

 of thumb, 4 lines. Apex hallucis, 5 lines. Skin covering buc- 

 cinator, 5 lines. Dorsum of second phalanx of fingers, 5 lines. 

 Palm of the hand, 5 hues. Surface of eyelid, 5 lines. Centre 

 of hard palate, 6 lines. Anterior surface of zygomatic process, 

 7 lines. Dorsum of the first phalanx of fingers, 7 lines. Out- 

 side of extremities of metacarpal bones, 8 lines. Mucous mem- 

 brane of lips close to the gum, 9 lines. Posteriot surface of its 

 zygomatic process, 10 lines. Lower part of the forehead, 10 

 lines. Back part of the heel, 10 lines. Occipital skin, lower part, 

 12 lines. Back of hand, 14 lines. Neck, beneath lower jaw, 15 

 lines. Vertex of the scalp, 15 lines. Patella, 16 lines. Skin on 

 the sacrum, 18 lines. Acromion, 18 lines. Glutaeus, 18 lines. 

 Superior and posterior surface of forearms, 18 lines. Leg near 

 the knee and near the foot, 18 lines. Dorsum of foot near toes, 

 18 lines. Sternum, 20 lines. Dorsal spine over five superior 

 vertebrae, 24 lines. Cervical spine near occiput, 24 Hnes. Lum- 

 bar spine, 24 lines. Centre of cervical spine, 30 lines. Centre 

 of dorsal spine, 80 lines. Middle of the arm where it measures 

 most in circumference, 30 lines. Do. of the thigh, 30 lines. 



This enumeration of relative distances, allowance being made 

 for all probable inaccuracies in the experimental estimate of 

 these distances, affords ample matter for reflection ; and fur- 



