CHAP. VII. STEPHENSON'S FIRST LAMP MADE. 109 



the business of the collieries and the improvement of 

 his locomotive engine, he was also busily engaged in 

 making experiments upon inflammable gas in the Kil- 

 ling-worth pit. As he himself afterwards related to the 

 Committee of the House of Commons which sat on the 

 subject of Accidents in Mines in 1835, he imagined that 

 if he could construct a lamp with a chimney at the 

 top, so as to cause a strong current, it would not fire 

 at the top of the chimney; as the burnt air would 

 ascend with such a velocity as to prevent the inflam- 

 mable air of the pit from descending towards the flame ; 

 and such a lamp, he thought, might be taken into an 

 explosive atmosphere without risk of exploding. 



Such was Stephenson's theory, when he proceeded to 

 embody his idea of a miner's safety-lamp in a practical 

 form. In the month of August, 1815, he requested his 

 friend Nicholas Wood, the head viewer, to prepare a 

 drawing of a lamp according to the description which 

 he gave him. After several evenings' careful delibe- 

 rations, the drawing was prepared, and it was shown to 

 several of the head men about the works. " My first 

 lamp," said Mr. Stephenson, describing it to the Com- 

 mittee above referred to, " had a chimney at the top of 

 the lamp, and a tube at the bottom, to admit the atmos- 

 pheric air, or fire-damp and air, to feed the burner or 

 combustion of the lamp. I was not aware of the precise 

 quantity required to feed the combustion ; but to know 

 what quantity was necessary, I had a slide at the bottom 

 of the first tube in ray lamp, to admit such a quantity 

 of air as might eventually be found necessary to keep 

 up the combustion." 



Accompanied by his friend Wood, Stephenson went 

 into Newcastle, and ordered a lamp to be made accord- 

 ing to his plan, by the Messrs. Hogg, tinmen, at the 

 head of the Side a well-known street in Newcastle. 

 At the same time he ordered a glass to be made for the 

 lamp at the Northumberland Glass House, in the same 



