168 History of' Mechanical Inventions and 



part of the voyage, and resisted the attempts of the captain and several 

 strong men to get the oil into the stomach- He continued to fail gradu- 

 ally, losing his appetite, and strength, until he died, much emaciated, soon 

 after the ship anchored. 



Captain Blanchard used to feel his pulse at the radial artery, and de- 

 scrihes it to be like the human. It was probably quicker. His mode of 

 walking was always erect, unless when tired ; he would then move or rest 

 on all-fours. 



Akt. xxxvii.— history of mechanical inventions 

 and processes in the useful arts. 



1. On a Method of Working an Air-Pump by continued Motion. By Wil- 

 liam Ritchie, A. M. Rector of Tain Academy. Communicated by the 

 Author. 



The method of working an air-pump by reciprocating motion is extreme- 

 ly inconvenient, and apt to injure the instrument by the sudden jerks to 

 which it is liable. The following method, by continued motion, is free 

 from these objections. Let there be two small wheels A, B, Plate I. Fig. 

 \-Z, having teeth completely round the semi-circumferences of one-half of 

 the thickness, whilst the semi -circumference of the other half has none. 

 The wheel A is turned by a handle in the usual way, and by the teeth, in 

 its entire circumference, gives motion to the wheel B in the opposite di- 

 rection. When the wheel A is turned, its teeth lay hold of those in the 

 piston rod CD, and raise it to its proper height. At the moment the teeth 

 in A lose their hold of the piston rod, those in B, moving in the opposite 

 direction, seize those in the rod, and bring it down to its former position. 

 The same will obviously hold true with regard to the piston rod EF. We 

 have thus a reciprocating motion in the two pistons produced by the con- 

 tinued motion of the two wheels. The same contrivance may obviously 

 be applied to the working of a mangle, and may, perhaps, answer better 

 than the common method. 



2. Account of Mr Brunei's New Power obtained by Liquefied Carbonic 



Acid Gas. 



Among the extraordinary contrivances of the present day must be rank- 

 ed the carbonic acid machine proposed by our celebrated engineer Mr Bru- 

 nei, who has secured his invention by an English patent, and also by a 

 French patent, in concert with MM. Ternaux and Delessert. Our read- 

 ers are already acquainted with the beautiful experiments of Mr Faraday 

 on the liquefication of several of the gases, among which was carbonic acid 

 gas. These experiments led several persons to conceive the idea of apply- 

 ing the liquified gases as the first movers of machinery, and Mr Brunei has 

 attempted to realize these views. 



In the apparatus which he has contrived, the first mover is liquified car- 

 bonic acid gas at the temperature of 50°, and under the pressure of 30 at- 



