A Guide To The Scientific Knowledge Of Things Familiar Part 15

Q. _Why will a_ ROOM SMOKE, _if there be_ TWO FIRES _in it?_

A. Because the _fiercer_ fire will exhaust the most air; and draw from the _smaller_ one, to supply its demand.

Q. _Why will a chimney_ SMOKE _if there be a_ FIRE _in_ TWO ROOMS _communicating with each other?_

A. Whenever the _door_ between the two rooms _is opened_, air will rush from the chimney of the _inferior_ fire, to supply the _other_; and _both_ rooms will be filled with smoke.

Q. _What is the_ REMEDY _in this case?_

A. Let a tube be carried from the hearth of each stove, into the external air; and then _each_ fire will be so _well_ supplied, that neither will need to borrow from the other.

Q. _Why do VESTRY CHIMNEYS so often SMOKE?_

A. Because the wind (striking against the steeple) _is reflected back_; and tumbles down the vestry chimney, forcing the smoke _into the room_.

Q. _WHAT WINDS make vestry chimneys smoke?_

A. Those from the north-east or south-east; according to the position of the vestry.

Q. _Why will the EASTERN winds make VESTRIES SMOKE, more than those from the west?_

A. Because they _strike against the steeple_, and _bound back_ to the vestry chimney: but _western_ winds cannot rebound over the roof of a church.

(N. B. The _steeple_ of a church is always due _west_, and the _other_ end of the church due _east_; if, therefore, a _western_ wind rebound, it would rebound to the _west_, or _away from the church_, and not towards it.)

Q. _Why does a HOUSE in a VALLEY very often SMOKE?_

A. Because the wind (striking against the surrounding hills) _rebounds back again upon the chimney_, and destroys its draught.

Q. _What is the common REMEDY in both these cases?_

A. To fix a _cowl_ on the chimney top, to turn like a weather-c.o.c.k, and present its back to the wind.

Q. _Why will not a COWL always PREVENT a chimney SMOKING?_

A. If the wind be _strong_, it will keep the _opening_ of the cowl _towards the steeple or hill_; and then the reflected wind will _blow into the cowl_, and _down the chimney_.

Q. _As a cowl is such a poor remedy, can any OTHER be devised?_

A. If the chimney flue can be carried _higher_ than the steeple or hills, no wind can enter the flue.

Q. _Why cannot the wind enter a chimney flue, if it be carried up HIGHER than the steeple or hills?_

A. Because the reflected wind would strike against the _sides_ of the chimney-flue, and not pa.s.s over the _opening_ at all.

Q. _In what OTHER cases will a CHIMNEY SMOKE?_

A. If both door and chimney be placed on _the same side of a room_, the chimney will often smoke.

Q. _Why will a CHIMNEY SMOKE, if the DOOR and STOVE are both on the SAME SIDE?_

A. Because when the door is opened, a current of air will _blow into the chimney-place_, and drive the smoke into the room.

Q. _What REMEDY can be applied to this evil?_

A. The door must be set _opposite_ to the chimney, or nearly so; and then the draught from the door _will blow the smoke up the chimney_, and not into the room.

Q. _Why will a CHIMNEY SMOKE if it NEEDS SWEEPING?_

A. Because the obstruction in the chimney (presented by the loose soot, to the free pa.s.sage of the smoke) _delays its current_, and prevents the draught.

Q. _Why will a CHIMNEY SMOKE, if OUT OF REPAIR?_

A. 1st--Because the _loose mortar and bricks_ obstruct the smoke: and

2ndly--The _cold air_ (oozing through the c.h.i.n.ks) _chills the air in the chimney_, and prevents its ascent.

Q. _Why will an ARNOTT'S STOVE SMOKE, if the joints of the flue do not fit air-tight?_

A. Because the _cold air_ (which gets through the joints) _chills the air in the flue_, and prevents its ascent.

Q. _Why does an old fas.h.i.+oned FARM CHIMNEY-PLACE so often smoke?_

A. Because the opening is so _very large_, that much of the air which goes up the chimney, _has never pa.s.sed near the fire_; and this cold air mixing with the other, so _reduces its temperature_, that it ascends very slowly, and the draught is destroyed.

Q. _Why does a chimney smoke, if the DRAUGHT be SLACK?_

A. Because, unless the current of air up the chimney be very powerful, it cannot _buoy the smoke up_ through the flue.