d that wouldn't be
agreeable."

"And the hot water: what is that for?"

"If we were to leave a tin containing melted dripping in a hot oven it
would get brown, burnt, smoky, and disagreeable?"

"But what has the water to do with the fat burning?" persisted Margaret.

"I will try to explain, if you on your part will try to understand
something which is difficult to understand. First of all, what is
boiling water?"

"It is water which is so hot that it bubbles all over, and steam rises
from it."

"Quite so. If we were using a thermometer, and were to put it into water
which was bubbling all over, we should find that the silvery line, or
mercury, in the thermometer rose until it came to 212 deg.. We might put a
hotter fire under the water, but under ordinary circumstances we should
never get the mercury higher than 212 deg.. Under extraordinary
circumstances, I confess we could get it higher. For instance, if we
were at the bottom of a mine, boiling-point would be two degrees higher,
and if we were to put some salt in the water, boiling-point would be
four degrees higher."

The little girls listened very attentively while Mrs. Herbert was
speaking. When she paused, they looked very solemn, and said nothing.

"Fat, on the other hand, can be made very much hotter: more than three
times as hot as boiling water. When heat is first applied to fat, it
bubbles, but as it gets hotter it becomes still. As it gets hotter and
hotter, it remains still, but it turns dark, and smokes, and smells
burnt. This is what would happen to our fat in the tin if we were to let
it come in contact with the heat of the oven shelf; but you can see that
when water, which never rises beyond 212 deg., is under it, it cannot burn
in this way."

"I see that perfectly," said Margaret, joyfully. "I like to be told
difficult things when once I understand them. But, mother, will not the
water boil away?"

"Yes; we must watch it, and as it does so, we must add fresh boiling
water. It would never do to add cold water, because that would make the
fat too cool, and would lessen the heat of the oven also."

"We should have to open the door, though, to see how the water was
getting on," said Mary. "Would not that be a pity?"

"It would have to be done in any case to baste the meat," said Mrs.
Herbert. "Remember, we can no more dispense with basting in baking meat
than we can in roasting it before the fire. If we try to do so, our meat
will be spoilt