1 873-] COWAN'S SYSTEM OF HEATING. 247 



lighted it keeps burning until purposely let out. The cold lime 

 is drawn out at the lower part of the kiln once or twice daily, and 

 the space left at the top filled with alternate layers of fuel and lime- 

 stone. Mr Cowan finds that once during twenty -four hours is 

 frequent enough for this operation, no further attention being 

 required in the way of firing until the time comes for the second 

 operation ; and the time necessary to do the whole work connected 

 wdth the kiln is just two hours of one man daily, including the break- 

 ing of the limestone, removing the lime, filling and putting everything 

 right for the day. The fuel Mr Cowan recommends is anthracite coal 

 or coke, from which there is next to no smoke ; but of course any fuel 

 which will burn lime in ordinary kilns will do for these. One of the 

 apparatus at Drumore has been at work for more than seven months, 

 and the other over three months. The first heats a vinery, a propagat- 

 ing house, and a plant-house. The other heats a range of vineries 

 200 feet long by 16 feet, and has 1000 feet of 4-inch pipe attached 

 to the boiler ; and both are ordinary saddle boilers, not by any means 

 large or of the best stamp of that class of boilers. Mr Cowan has 

 arranged for the manufacture of an improved boiler to take the place 

 of such as he has made a beginning with — a model of which we have 

 seen, and which must be powerful and conservative of heat when placed 

 over the lime-kiln. But where the amount of heat required is not very 

 great, the ordinary saddle does perfectly well, and is to be recommended 

 on account of its cheapness. When the kiln is required to be kept going 

 and heat not required in the houses, if such should ever be a necessity, 

 Mr Cowan makes provision for this by fixing a supply cistern very much 

 larger than an ordinary one near the boiler, and connecting it with both 

 the flow and return pipes, and by turning the valves the heat can be 

 turned from the houses to this cistern without any danger to the 

 apparatus. 



With regard to the saving or compensating capabilities of the 

 system, it is found that as much good lime is produced as pays the 

 whole cost of fuel at Drumore, where coal costs 25s. per ton, and it 

 just requires the two hours' labour of one man per day for the heating 

 done. Of course the larger the apparatus the better it would pay; and 

 in districts where coal is cheaper and lime dearer, it would tell much more 

 in favour of the system. Mr Cowan just gets 5d per bushel for the lime. 



These remarks, we hope, will give some idea of the system Mr Cowan 

 has found to answer his purpose completely, where economy is of first- 

 rate importance ; and surely it is well worthy a trial at the hands of 

 those who can procure either chalk or limestone. Those who have 

 seen the system in active operation at Drumore speak in the highest 

 terms of its efficiency. 



