140 
A 50. 
No. 19, C, is part of a ring carved with great accuracy, and 
highly polished ; found in Ohio. These rings usually measure 
about two inches and three-quarters in diameter, and are about 
half an inch in thickness. They are deeply grooved upon the 
outer edge, and are pierced by eight small holes, at equal 
distances from each other, all converging to the centre. 
Several rings of rather larger dimensions were obtained, some 
years since, from a mound at Cincinnati. Similar rings, of 
smaller size, made of bone, have also been found. No. 20 is 
a cast representing No. 19 restored. 
The perforations and hollows of the mound-pipes, and of some 
other objects, are drilled with extreme accuracy, showing that 
the tool used was not merely turned between the hands, but 
was moved by an arrangement probably resembling the ''bow- 
drill" used by watchmakers and others. The ordinary "bow- 
drill" consists of a straight tool, which passes through the 
centre of a disc grooved on the outside, motion being imparted 
to the tool by means of a bow, the string of which is made to 
encircle the disc. It appears probable that a ring, such as No. 
1 9, may have formed part of a drilling apparatus somewhat of 
this kind. 
Nos. 16 to 18, 23 to 26, and 28 to 30, are fragments of stone 
smoking-pipes, from Mound No. 8, " Mound City," shown to 
illustrate the mode of drilling practised by the mound-builders. 
No. 21 is a thin tablet of clay slate, one inch and seven- 
eighths in length, one inch and a quarter in width, and rather 
more than an eighth of an inch in thickness. It is perforated 
with five large and six small holes, and was found in Ohio. 
No. 22 is also of clay slate ; it was found in Ohio, and is 
pierced with seventeen holes. It measures two inches and 
seven-eighths in length ; its greatest breadth is one inch, and 
it is of the same thickness as No. 2i.f No. 27 is a piece of 
green chlorite, considered by Dr. Davis to be the roughly 
blocked out commencement of a smoking- pipe of the mound 
type. The tablets Nos. 31 and 32 are noticed at page 119; 
Nos. 33 and 34, at page 124; Nos. 35 to 37, at page 119. No. 
* Nos. 16, 17, 28, and 29, are of limestone; Nos, 18 and 30 of 33, see 
page 107 ; Nos, 23 and 24 of 33, dark var.; Nos. 25 and 26 of 33, liglft var. 
t Professor Church has suggested that the tablets, Nos, 21 and 22, were 
used as gauges, or were in some way connected with working in thread. 
