120 BULLETIN 173, U. S. NATIONAL MUSEUM 



and pointer in a quadrant case above the cylinder. To operate the 

 gauge the piston is raised by the handle to the top of the cylinder and 

 then brought sharply down "so as to act with percussive force upon 

 the surface of the water by which it will be suddenly arrested", thug 

 indicating the height of water in the boiler. "This apparatus has 

 been attached to a boiler furnished with the ordinary try cocks, and 

 has proved them to vary in some instances, four inches and a half 

 from the truth, while the indications by percussion have been un- 

 varying." 



FRICK FEED-WATER APPARATUS, 1858 



U.S.N.M. no. 308661 ; original patent model ; transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent 

 issued to Jacob Frick, of Philadelphia, Pa., December 14, 1858, no. 

 22284. It is an improvement on the patent issued to Frick, March 

 18, 1856, no. 14449. 



The model represents a combination of an air chamber, a safety 

 valve, feed-water and blow-off cocks, a feed-water failure alarm, 

 and a water jet for extinguishing fires, all arranged in one instru- 

 ment so that all can be secured to the boiler by one attachment only, 

 thereby avoiding the necessity of piercing and "wounding" the 

 boiler in several places. 



GILL STEAM-PRESSURE GAUGE AND ALARM, 1859 



U.S.N.M. no. 308917 ; original patent model ; transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent 

 issued to W. Y. Gill, of Henderson, Ky., March 8, 1859, no. 23166. 



The invention represented by the model consists in constructing 

 the piston of a gauge in which a piston acts in opposition to a coiled 

 spring so that the upper portion of the stem of the piston may be 

 marked with indications on several sides, while at the same time the 

 lower part of the cylinder is pierced with a number of openings 

 through which steam will escape and attract attention when the 

 piston is forced beyond the opening by the pressure of steam in the 

 boiler. 



The gauge resembles the familiar automobile-tire pressure gauge 

 of similar construction except that the indicating stem is attached 

 to the piston and rises and drops with it. The inventor suggests 

 that if the piston is made a loiown part of a square inch the gauge 

 can be calibrated or checked very simply by turning it upside down 

 and hanging weights on a ring provided at the end of the stem. 



