THE GEOLOGIST AWHEEL. $17 



these occasions to remove the ordinary type of cyclometer lest it be 

 broken or injured in handling. All this danger is avoided in the im- 

 proved form of cyclometer which is attached to the center of the axle. 



The equipment of the geologist will generally consist of a collecting 

 bag with separate compartments for note book, maps, and rock speci- 

 mens; a hammer, compass and aneroid barometer. In regions of low 

 relief the aneroid is of little service and may be dispensed with, but the 

 best method of carrying the other articles of the geologist's equipment is 

 a question of considerable importance. 



The collecting bag which is in use by government parties operating 

 in the northern Atlantic States may be deserving of a special description, 

 inasmuch as it is an evolution of many years. It is made of the best 

 grade of russet leather and has four compartments. The map compart- 

 ment is merely a double back within which the maps, properly pro- 

 tected, are slipped. The note book compartment is sewed on the front 

 of the bag and shaped to the book. In the main central compartment 

 of the bag the specimens are stowed and in a wide but shallow pocket 

 sewed to its back near the top are kept the black and colored pencils, the 

 eraser, horn protractor, and small ebonite triangle, for use in the making 

 of notes and in plotting the observations upon the map. The cover of 

 the bag is a flap fastened by a strap to a buckle on the front and near the 

 bottom of the note book compartment. When carried on the person the 

 bag is supported by a wide strap passing through loops on the sides and 

 bottom so as to carry the weight from below. On the wheel the bag is 

 supported by a light framework of strong galvanized iron wire, which by 

 means of three leather straps is securely fastened to the handle bar and 

 the head of the machine. The bag fits loosely into the frame, even 

 when filled with specimens, and it is kept in place on rough roads by 

 being attached by two straps furnished with snaps to the handle bar of 

 the bicycle. The bag can thus be almost instantly attached to the wheel 

 or removed from it and slung by the carrying strap over the shoulder. 



The topographic map sheets which are used for the base in the geo- 

 logical work are cut in half and each of these halves is again divided so 

 as to be mounted on the inside of two cloth covered and hinged boards, 

 as is the lining to a book cover. This method of mounting secures a 

 smooth surface and a firm support to the map, gives a large area always 

 at hand so that geological relationships may be easily appreciated, and 

 furnishes moreover the best possible protection to the records of the 

 work. Hardly less important is the protection which these stiff boards 

 afford to the leather back of the bag when they are slipped within its 

 map compartment, and also to the body of the geologist when the bag 

 is loaded with heavy specimens and carried from the shoulder. 



The best form of compass is doubtless the four-inch aluminum dial 

 compass with clinometer attachment, which is manufactured by Gurley 



