VI. VELOCITY. 79 



410. Lowne's Portable Air Meter, originally introduced 

 by Casella. R. M. Lowne. 



The indications of this instrument are obtained by means of a light fan 

 which communicates motion to indicating wheels ; the dial of the instrument 

 is placed at right angles to the fan, and is supported by three pillars on a base, 

 which also supports the tube containing the fan. The works are extremely 

 sensitive, the first centres running in jewels, and the indicating parts can be 

 thrown in or out of gear with the fan. 



410a. Lowne's Patent Magnetic Anemometer, espe- 

 cially adapted for measuring currents of air, gases, and fluids in 

 positions where delicate instruments would be subject to corro- 

 sion. R. M. Lowne. 



The peculiarity of this instrument is, that the registering works are en- 

 closed in an air-tight chamber, the connexion of the revolving fans with the 

 works being made through a sheet of brass by magnetism. The fans carry a 

 small bar magnet, and the first wheel of the indicating mechanism carries a 

 piece of soft iron, so that when the fans revolve outside the plate of brass the 

 soft iron revolves within by attraction and thereby moves the works. 



41Ob. Lowne's Patent Colliery Air Meter, constructed 

 expressly for use in mines. R. M. Lowne. 



The external aspect and form of this instrument is that of the well known 

 " Byron's Anemometer." The improvements consist of. 1st, a strong, light, 

 and anti-corrosive fan ; 2nd, a large clear dial ; 3rd, the indicating parts are 

 perfectly protected from dust and smoke, this being done by a practical mecha- 

 nical arrangement ; and 4th, a lever is placed in a convenient position to enable 

 the observer to throw the indicating wheels in or out of gear with the fan. 



41Oc. Lowne's Patent Magnetic Anemometer and 



Current Meter, for measurement of velocity of currents of air, 

 gas, and fluids. R. M. Lowne. 



In this instrument the registering works are enclosed in an air-tight cham- 

 ber, the connexion of the revolving fans with the works being made through 

 a sheet of brass by magnetism. Gymbals accompany this instrument, with 

 direction vane, for use on board ship. 



410d. Lowne's Patent Ventilation Anemometer, origi- 

 nally introduced by Stanley. R. M. Lowne. 



This instrument measures the air by means of a fan wheel placed in a clear 

 opening, without any obstruction from the registering apparatus, which is in a 

 separate chamber on the same plane as the fans, so that the instrument is quite 

 flat for the pocket ; the whole of the works are of extreme sensitiveness, and 

 the axes of the fans run in jewels, the indicating hands give the current that 

 passes the fans in feet (after correction), and a lever above the dial throws the 

 registering works in or out of gear with the fans. 



410 e. Mining Anemometer, for showing the velocity of cur- 

 rents in mines. Elliott BrotJiers. 



410f. Biram's Anemometer. Improved for Coal Mines. 



Francis Pastor elli. 



