The log cabin Democrat., 1911-03-10

an inexperienced operator realizing that the incubation is not progressing in a satisfactory manner, In addl- ton, the air cells may be of the prop rsize and yet the bryo may perish, either on account of an insufficient amount of oxygen, or because the gases resulting from the growth of the embryos are not carried away with sufficient ripidity.
 It is unnecessary to describe in de- tail the stages in the development of chick. The cihck, however, absorbs oxygen and moisture and certain gas es are thrown off through the shell. Under normal conditions the total amount of moisture and gases which have been thrown off at any partlcu lar stage in the development of the chick, or, in other words, when the egg is incubated under perfectly nor maj conditions the total loss in the weight of teh egg corresponds, within certain limits, to the stage of develop ment of the embryo.
 "If the operator of an incubator knows how much a certain number of eggs have lost in weight since the be- ginning of the incubating period and compares this loss with the normal loss of the same number of eggs for the same length of tibe, he will know definitely whether the eggs have de- creased proportionately in weight. If they have lost too much, provided, of course. the temperature has been nor nal, they are drying up too rapidly, and either more moisture should be supplied or the amount of ventilation should be reduced; but in reducing the circulation of air through the incu- batting chamber it must be remember ed that pure air surrounding the eggs is just as important a sa proper tenn nerature. On the other hand, if the eggs are not losing weight as rapidly as tehy should they are either kept too moist, or are not receiving the proper amount of ventilation, or per haps they may be kept too moist and insufficiently ventilated also
 "The object of this bulletin is to | furnish sufficient data to enable the operators of incubators to exercise a more intelligent supervision over the operation of their machines. A num- | Der of experiments have been per | formed to determine the nomal loss in the weight of eggs during the in cubation, and for this purpose the natural method of matching has beer | employed. Eggs have been weighed placed under brood hens in locations suitable for a perfect hatch, reweigh- ed on a chemical balance at suitable intervals and the loss determined"
 As a ersult of the studies detailed in Bulletin No. 73, directions were is sued covering the practical points in volved, and as these directions are al so out of print, they are reproduced herewith:
 After placing the eggs upon the trays ready for the incubator, set tht trays upon a pair of scales reading to ounces and note the total weight of the eggs and trays (the trays should be thoroughly dry). After { few days weigh again. Subtract this from the first weight This will give the actual loss in weight of the eggs
 Example: Suppose you have pos eggs on the trays; that the first weight with trays is 24 pounds 7 ounces, and that on the sixth day the weight is 23 pounds 6 ounces. Then | look in the table for the loss in weight of 100 eggs for six days. This is 10 ounces, 10 ounces multiplied by POS gives POS ounces, which is the calcu- lated loss for POS eggs in six days. Therefore, the eggs have ont been los ing weight as rapidly as they should, and the eggs should be given more ventilation or the incubator should be removed to a drier location. Cit is assumed that the eggs are kept uni formly at the proper temperature.) After the eggs have been tested for the unfertile ones, weigh again and proceed as before.
 "If the eggs have lost too much weight give more moisture or less ventilation but in reducing ventila- tion great care should be used, as pure air in the egg chamber is abso- lutely necessary.
 "If the eggs have not lost enough weight open the ventilators, or place