relating to Gas Illumination," 39 



from the gas, How can there be ? For when it testa Trski^-o 

 part of sulphuretted hydrogen, the lime for purifying is changed. 

 That this test is very possible as well as very easy, let me refer 

 your readers to the evidence borne by Dr. Henry in his late va- 

 luable '* Experiments on the Gas from Coal." When speaking 

 of the method of purifying by lime, adopted by his friend Mr. 

 Lee : " After the second purification," says he, " the gas produces 

 no change whatever in the test, which preserves its perfect white- 

 ness, thereby demonstrating the complete removal of sulphuretted 

 hydrogen. In this state of purity its odour (even prior to com-- 

 bustionj also is so much diminished as scarcely to be at all of- 

 fensive. Besides, can we for a moment believe that Mr. Lee 

 would be at the trouble of conveying it in portable gasometers 

 for '* supplying his house, two miles from the manufactory," if 

 it luas so fraught with this health-and-furniture-spoiling pro- 

 perty? Again : the ceilings of our rooms, too, are just as white as 

 before the introduction of the gas ; and the slight, though equally 

 diffused, heat arising from it, is considered an acquisition, rather 

 than a source of accusation. This at once furnishes us with a 

 ready answer to the latter clause of the paragraph we have been 

 examining ; where it is stated that free " hydrogen is also formed 

 and mixed with it in a large proportion, which on being ignited 

 occasions great heat without adding to the light : these effects 

 render coal gas unpleasant in sitting-rooms, and have nearly con- 

 fined its use to open shops and street lamps." Have nearly 

 confined ! In the first part of the paragraph we are given to un- 

 derstand that it is altogether 6o confined ; and that its innume- 

 rable and insuperably bad qualities " exclude its use from dwell- 

 ing-houses ! ! " How much more edifying it would have been, 

 had the writer favoured us with more experiments and fewer 

 assertions by ways of proving to us, that a gas {oil gas for in- 

 stance) consuming twice as much oxygen during combustion, as 

 another (coal gas) should yet give off less lieut ! His observa- 

 tions on coal gas illumination must surely have been confined to 

 the streets of London, where (with all due deference to the me- 

 tropolis) it is more disgraced than in any place where I have yet 

 seen it ; not by the manufacturers of it, but by its wasteful and 

 unscientific consumers. The writer, if he is not bodily blind, 

 may convince himself that in many large towns in the country 

 it is not " excluded from dwelling-houses," 



The first sentence of the next paragraph,'respccting the stop- 

 ping up and destroying of the smaller pipes, by the action of the 

 sulphuretted hydrogen, is already answered, by showing that it 

 is very possible as well as very easy to remove the cause. But 

 the latter clause so obtrudes itself upon the eye, and so manifestly 



C 4 betrays 



