TRANSACTIONS OF THE SECTIONS. 159 



top globe, repeats the operation, and the speed at which the globes 

 oscillate will be precisely in pi-oportion to the quantity of gas which 

 has been blown upon them, provided a uniform difference of tempera- 

 ture is always maintained between the two streams of gas. The dif- 

 ference of temperature is established and rendered uniform by a small 

 flame of gas, which heats a chamber through which the lower current 

 of gas has to pass, and the arrangements for securing an equality in 

 the difference of temperature are very ingenious. The instrument is 

 first tested by making a given quantity of gas pass through it, and ob- 

 serving the immber of oscillations of the pulse-glass. This once esta- 

 blished, the instrument registers the quantity passed with extreme 

 accuracy. 



Sir John Robison mentioned a circumstance which he considered of 

 peculiar importance to the lower orders. Mr. Strutt, of Derby, to 

 Avhom the country owed so much, had some years ago expressed to him 

 an opinion, that coal-gas would be found by the lower orders the 

 cheapest fuel for cooking. This he had applied ; and the whole appa- 

 ratus, which might be considered as the converse of the Davy safety- 

 lamp, consisted in fixing a piece of wire-gauze at the extremity of a 

 gas-pipe of about six inches in diameter. He referred to the account 

 in Loudon's ' Encj'clopaedia of Cottage Architecture,' for some valuable 

 remarks and directions on this subject. The wire-gauze was liable to 

 be destroyed under a long-continued intense heat : this, however, Avas 

 obviated by sprinkling a small quantity of sand upon it. Bulk for 

 bulk, gas was more expensive than coal, but the former was more eco- 

 nomical and convenient for occasional use and the smaller operations 

 in cooking. 



Sir John Robison explained a model of the bucket of a pump in use 

 in Sweden, the peculiar feature of which was, that the pressure of the 

 sides of the bucket outwards against the pipe is exactly pi'oportional 

 to the load to be raised. This bucket is peculiarlj' applicable for rai- 

 sing foul water. 



On a New Day and Night Telegraph. By Joseph Garnett. 



The paper on this subject was accompanied by a model, to exhibit 

 the construction and method of working of the telegraph, which it is 

 proposed should consist of two ladders, about 41 feet long, framed 

 together at about 24 inches asunder at the bottom, and 20 at the 

 top, so as to constitute the frame for the machinery. There are two 

 arms, one at the top, the other about midway up the frame-work, coun- 

 terpoised by weights, and worked by machinery, consisting of 8 bevel 

 mitre wheels. At the bottom of the frame-work is a dial plate, with a 

 pointer, and the workman, in setting the pointer, brings the arm of the 

 telegraph into the required corresponding position. 



