"rain," "fair," etc., if required. It is presumed that reference can be made to a standard barometer for the purpose of determining the points of the scale. Two comparisons should be made on different occasions, once when the stanrlard instrument is very low, and once when it gi\es a high reading. Say the two readings are 27 and 31 ins. respectively. Then the distance between the two corresponding positions on the home- made barometer may be provisionally divided into 40 equal portions and called tenths of an inch, the figures being marked to correspond. But an effort should be made to check as many of these intermediate positions as pos- sible by comparison with the standard instrument. — H. J. Gr.w.
Killing Vermin with Gas
HVDROCYAXIC-ACID gas is one of the most efficacious agents in rid- ding households of such pests as bedbugs, fleas, cockroaches, ants, clothes-moths, etc. Rats and mice, when exposed to its fumes, run out of their holes into the open and die there. There is thus no subsequent annoyance from dead rodents in the walls and under flooring.
Even when only one room of a house is to be fumigated the entire house must be vacated and so closed and marked with signs that everyone is kept out. The windows in such a house must be equipped with ropes so that they can be opened from the outside when the fumigation is done. If the house is close to another, especially if its windows are below those in an adjoining house, care must be taken to protect neighbors. This is especially necessary in the case of a house in a row, particularly if the partitions separating houses are not tight, or if its attic or roof air-space com- municates with those in the neighboring houses. For these reasons, in the case of summer cottages at beaches, it is safest and easiest to fumigate before the family or neighbors have moved in, when there is plenty of time to air the house com- pletely after it has been treated.
While hydrocyanic-acid gas is proba- bly the most efficient means of ridding a house of vermin, it is also one of the most deadly poisons. Therefore, the greatest care should be exercised in its use.
��Popular Science Monthly
A Wallpaper Remover
��THE difficulty and incon\enienre inci- dent to the removing of old wall- paper and the preparalif)n of the wall for redecoration are reduced to a minimum by the use of a new tool that gets at the root of the trouble. It works under the paper, or, rather between the paper and the wall, softens up the paste or glue and freely strips the paper from the wall.
���Every bit of wallpaper should be removed before beginning the work of repapering
It is particularly adaptable where there are se\"eral layers of paper to be removed, or for stripping oft' e.\tra hea\'y or varnished paper. The usual way of Hooding the walls with water or filling the room with steam are not necessary. The simple mechanical device illustrated generates steam on the spot with a gasoline burner and the steam is con- trolled by a vaKe in the hand-piece where it is driven behind the paf)er in a thin sheet.