38 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Report on Lamps to burn Coal Oil without a Chimney. 

 The lamps referred to me for examination were received in 

 the following order : 



No. 1. Thomas's. 



2. Kaestner's. 



3. Isaacson's. ' 



4. Miller's. 



5. Smith's. 



6. Dietz & Co. 



No standard requirement was fixed for the competition, and the 

 lamps must alike seem only to have this much in common, name- 

 ly, that they will all burn on the top of a pint cup. Comparative 

 results must, therefore, be regarded as approximations. 



The evil against which they have to provide is simply blacks 

 that smell ; almost any naked flame can bo made to smoke ; but 

 Nos. 1, 2, 4 and 6 will do so when carried about with such a 

 draft of air as may be made by persons quickly passing, or by 

 quickly shutting even a distant door. No. 5 is in the same cate- 

 gory when burning enough coal oil to give a useful amount of 

 light. It has been objected by Mr. Smith that other lamps can 

 be put out by suddenly lifting them up. This is seldom the case 

 with less motion than equals running up stairs, unless they are 

 previously pulled downwards. It is to be remarked that the 

 blacks are not accompanied with injurious products of decom- 

 position, as in the case of imperfectly burnt alcohol, or tallow. 

 No headache results; nor is there any acid generated, as there 

 is from foul gas. This does not apply to the vapors escaping 

 unburnt after contact with heated metal as in lighting Nos. 1 

 and 2. Entire cleanliness is of the greatest importance in the 

 use of these lamps. Every part of them should be accessible to 

 remove fragments of matches, spilt oil, &c. A small piece of 

 dirt adhering to the burner has been observed to cause smoking. 

 Offensive smells cannot otherwise be prevented. In this respect 

 Nos. 1 and 2 are more defective than others. 



The important properties of coal and petroleum oil, for lamp 

 purposes, consist in its capillarity and the non-adhesiveness of 

 the solid matters deposited from it. The latter are easily de- 

 tached from the wick where this is accessible, as in Nos. 3, 4, 5 

 and 6. Too much has been expected from the first of these. It 

 will, no doubt, enable a supply to be drawn up three or four 

 inches. In none of these lamps is it indifferent whether the level 



