552 DOMESTIC ANIMALS, DAIRYING, ETC. 



turb the level of the incubator. The sash of the door should be 

 heavy enough for strength, but not so wide as to interfere with the 

 view of the eggs or the thermometer. The glass in the door should 

 be wide enough in the perpendicular to afford the operator a full 

 view of the egg chamber without stooping or kneeling. It is not 

 a view of the wooden edge of the tray that the operator wants ; it ig 

 a view of the thermometer, the eggs, or the chicks. The glass 

 should be located so as to permit this view, but if the glass is too 

 narrow or not properly placed, or if the margin of the sash is too 

 wide, the window will be of little value to the operator. This 

 matter is worthy the attention of the manufacturer, for there is quite 

 a prejudice against a machine the temperature of which can not be 

 watched without the removal of the thermometer from it. Many 

 manufacturers send machines with doors imperfectly fitted, the glass 

 of which is covered with paint, putty, or varnish, which can not be 

 removed, and it is impossible to read the thermometer through such 

 doors. Once more purchasers are warned to avoid the machine that 

 will not permit them to read the thermometer without opening the 

 door. Manufacturers should bear in mind that the light should 

 strike the egg tray from above instead of from below. 



Thermometer. It is really surprising that up to the present 

 time so little improvement has been made in thermometers. An in- 

 strument of this kind should be plainly legible and it should be con- 

 venient to handle. The usual practice of glazing the back of the 

 tube with white porcelain makes the reading of the temperature very 

 difficult. There seems to be no good reason for this. This white 

 background makes a grayish shade, the color of the mercurial col- 

 umn, and unless the light is very good and strikes the figures from 

 the right direction it is almost impossible to ascertain the tempera- 

 ture without removing the thermometer from the machine. This is 

 bad, as the column is likely to contract or expand while being con- 

 veyed to the light. The column should be large enough to be seen 

 from a distance of at least 4 feet, and the markings and figures 

 should be few and very plain. Many of the frames in which the 

 glass is set are cumbersome, take up too much room, obscure the 

 view, have sharp corners or long legs to catch upon the tray or 

 sleeve, and yet are too unstable to stand alone or stay where placed. 

 A thermometer with a red or green background, a large mercurial 

 column, a few plain marks and figures, and mounted upon a con- 

 venient yet substantial frame will be a boon to poultry men. Im- 

 provements will be made, and it is well for purchasers to ask for the 

 latest and the best. In connection with thermometers it is well to 

 state that the so-called "magnifying lens" is a failure and much more 

 difficult to read than the plain round tube unless it is held in exactly 

 a certain position with reference to the light. The thermometer tube 

 need not be over 4 inches long, and the less metal it has attached to 

 it the better. In regard to the accuracy of the thermometer, almost 

 any physician will test it for you by the side of his clinical ther- 

 mometer, which has about the same scale and range. 



