Xew York Agricultural Experiment Station. 137 



COST. 



Cost of construction. — If no allowance be made for the time spent 

 by members of the Station staff in supervision, the cost of construc- 

 tion was as follows: 



Carpenters (labor) $134 00 Other electrical fittings. ... $15 00 



Cork-board 45 00 Zinc and galvanized iron fit- 

 Cement for cork-board 11 50 tings (and labor) 34 00 



Lumber 67 90 Hinges, door-clasps, screws, 



Mason (labor and materi i!s).. . 17 00 nails, etc 12 00 



Finish (paint, varnish, etc.) ... 10 00 



Plumbing 23 00 Total $381 75 



Thermostats (and heating wire). 12 35 = 



Cost of maintenance. — The incubator has proved especially 

 economical in service. The only cost of maintenance has been for 

 ice and electricity. Ice consumption is very moderate. During 

 the spring, while the room temperature averaged 21°, it was found 

 that 216 lbs. of ice lasted 12 days. Assuming the cost of ice to be 

 $5 per 2,000 lbs., this makes the cost $0.30 per week; and as the 

 week was of about average temperature, it may be concluded that 

 the cost per year is about $15 for ice. 



The cost of the current consumed is also moderate. The insula- 

 tion is so effective that approximately only one watthour a day is 

 consumed per square foot of wall per degree Centigrade difference 

 in temperature outside and inside. To make allowance for the 

 occasional opening of the doors when the incubator is in moderate 

 use, 10 per ct. is a fair amount to add to this, although the heat 

 loss from this cause varies with the temperature of the incubator, 

 temperature of the room, and frequency of opening the doors. 

 These figures, however, are useful only for rough computation, as 

 they were obtained by means of a commercial meter 5 which had 

 not been standardized and was adapted for higher loads than fur- 

 nished by the heaters. The radiation through cork-board of one 

 inch thickness, as stated by the manufacturing company, is 6.0 

 British Thermal Units per square foot, per degree Fahrenheit 

 difference in temperature. Based on this estimation, 0.786 watt- 

 hours a day would be required for four-inch cork-board per square 

 foot per degree Centigrade difference in temperature. 



In actual use this has worked out as follows: With an average 

 room temperature of 19° C, and the incubators in constant use at 

 37°, 30°, 25°, and 18°, respectively, 730 watthours have been con- 

 sumed per day or about 255 kilowatthours per year. Allowing 

 a cost of $0.10 per kilowatthour, the total cost per year is only 

 $25.50. 



5 Thomson Watthour Meter (2 wire): Volts 100-110: Amp. 5; loaned by the 

 courtesy of the Central New York Gas and Electric Co., Geneva, N. Y. 



