12 FIELD GEOLOGY. 



boring to digging through the soil this is done by a 

 gouge-like spud attached to the lower end of a stick or 

 a long hammer-handle ; it can be either removable or 

 permanently fixed. This, when pressed into the earth 

 and screwed round, will make a hole from a foot to 2 

 or 3 feet deep, according to the hardness of the mate- 

 rial, and bring up cores as specimens from the bottom. 

 In figure 3 is represented a combined hammer, pick, and 

 spud ; with the latter unscrewed the hammer does duty 

 for a walking-stick, and altogether it is as useful and por- 

 table a set of implements as can be carried by a Geologist. 



Fig. 4. Protractor, underside as scale (half size). 



Scales. For the purpose of measuring distances on 

 the map a scale is required, the most useful size being 

 6 inches long. The carrying another instrument may 

 be saved by having the reverse side of the protractor 

 divided (fig. 4), on the one edge into 80 parts for use 

 with the six-inch maps, each part representing a chain. 

 The other edge, for use with the one-inch maps, must 

 be divided into inches, and each inch into 40 parts re- 

 presenting 2 chains : smaller sub-divisions would be too 

 minute. The otherwise plain edge (on the degrees side) 

 of the protractor may with advantage be divided for a 



