15 



42. An improved Marine and Mountain Barometer. — By 

 Sir David Milne. 



The construction of this instrument allows it to be used as a Marine 

 Barometer. In the middle of the tube, or half way down, the bore is 

 reduced to the size of an ordinary thermometer bore, in consequence of 

 which the mercury is prevented from flowing rapidly and violently into 

 the upper part of the tube, when the instrument swings about. The 

 open end of the tube through which the atmosphere acts on the mer- 

 cury, is so constructed, that the mercury does not run out or escape 

 when the instrument is upset. 



43. Patent Safety Spring for Carriages. — By Barton. — This 

 spring unites greater strength and safety with a much less weight 

 of material than is contained in the ordinary carriage spring. 



44. Portable Mercurial Pendulum. — By E. J. Dent, London. 



45. Pneumatic Apparatus.— By Dr. Clanny. — For extract- 

 ing and analysing the air contained in blood, and other fluids, at 

 low temperatures by which the possibility of chemical changes 

 by the action of heat is prevented. — See Lancet, 23rd Aug. 1834. 



46. Apparatus for receiving blood from the hand in tepid 

 water. — By Dr. Clanny. 



47. Apparatus for receiving blood in vacuo. — By Dr. Clanny. 



48. Instruments for crushing Stone in the Bladder. — ^John 

 Brown and Son, Grey-street, Newcastle. 



49. A new Chuck for turning Wire into Screws, <^c. or for 

 holding Drills. — By Charles T. Couthope, Bristol. 



50. HalPs Patent Hydraulic Belt for raising Water. 



A woollen belt is passed over a roller at the top of the shaft and under 

 one at the bottom, and by giving the belt a velocity of about 1000 feet 

 per minute, the water adheres to the belt, and is brought up and dis- 

 charged into a trough by the centrifugal force in passing over the top 

 roller. It possesses most important advantages over the pump, and is 

 particularly applicable to coal pits, mines, &c. &c. 



1st. — Producing more water with the same power. 



2d. — The economy in cost and repairs. 



3d. — The saving of time during the repairs, &c. 



51. Model of the present House of Commons, illustrating 

 the ventilating arrangements introduced by Dr. D. B. Reid. 



