10 



THE GARDENER'S MONTHLY 



[January, 



majus, 0. vexillarium, 0. Roezlii, Cwlogj-ne cris- 

 tata, Oncidium Kramerianum, O. incurvum, O. 

 flexuosum, 0. varicosuni, Phalsenopsis Schilleri- 

 aiia, P. amabilis, P. grandiflora, and a large im 

 portation of Lielia mnjalis, with numbers of 

 others, are in such condition of strength and 

 vigor as is not usually met with. A fine stock 

 of the New Anthurium Andreanum, an 

 extremely attractive plant when in fiower. It 

 remains in perfection for three months, render- 

 ing it a valuable plant ; the cultivation required 

 is the same as A. Scherzerianum, of which the 

 Cincinnati Floral Company have a large stock. 

 To give the public some idea of the import- 

 ance of this collection, this company was 

 awarded at the Cincinnati Industrial Exposition 

 of this year no less than fifty-two first prizes for 

 plants. Their Crotons, Palms, Ferns, Pandanus, 

 Musas, Marantas, Dieflfenbachias, Caladiums, 

 were grand objects of cultural skill, filling an 

 area of nearly six thousand feet in the horticul- 

 tural hall. 



A HOTHOUSE ALARM TO GUARD 

 AGAINST FROST OR GREAT HEAT. 



BY CHAS. DUDLEY WARDE, CONCORD, N. H. 



To any one who has had the care of a hot- 

 house during one of our terrible northern win- 

 ters, the mere mention of a frost suggests hours 

 of anxious watching and apprehension. I have 

 sometimes thought that the pleasure taken in 

 my hothouse during its first winter was more 

 than counterbalanced by the constant anxiety 

 and fear lest by some unforeseen circumstance 

 the little silver column should drop below the 

 fatal point, 32°, and in an hour the result of the 

 patient labors of months, and the objects of my 

 especial pride, should turn to blackness and de- 

 cay. This fear grew 'to become a perfect night- 

 mare, and my slumbers were frequently dis- 

 turbed with visions of plants frozen and covered 

 with ice. One cold night, after having made 

 three visits to the hothouse to see that all was 

 right, I resolved that something must be done, 

 and commenced soon after to investigate the 

 subject of electricity and its adaptation to burg- 

 lar and fire-alarms. After a series of futile ex- 

 periments, I obtained a small Hat rod or bar 

 about twelve inches long, three-eighths inch 

 wide, and one-sixteenth inch thick, formed by a 

 thin piece of brass and a similar piece of steel 

 fastened securely together. This was suspended 

 by one end being firmly fastened in a small 

 block of wood placed on a board, and the rod 



was so placed that the free end could swing back 

 and forth and just clear the board. On both 

 sides of the bar, and about one inch from it, 

 near the free end a thumb-screw was placed, so 

 that if the bar be moved it would strike the ends 

 of the screws. The end of the bar was fastened, 

 and the screws were so arranged as to be esisily 

 connected with wires. Now the well-known law 

 of physics that "heat expands and cold con- 

 tracts" is true in metals, but in a different de- 

 gree, and by consulting the tables of the expan- 

 sive qualities of metals it will be found that steel 

 and brass are widely difierent in this respect, 

 and in the arrangement above described it was 

 found that when heat was applied the brass ex- 

 panded more than the steel, causing the rod to 

 bow, and the free end to swing in the direction 

 of the screw on the steel side of the bar ; and 

 the application of cold caused the brass to con- 

 tract more than the steel, and the bar to swing 

 in the other direction. By testing this machine 

 in various different temperatures, it w-as easy to 

 make a scale, and to place the thumb-screws so 

 that the end of the rod would touch them at 

 any given point of temperature. Then obtain- 

 ing a common electric call bell, and a battery, 

 such as the telephone companies use (any good 

 battery will answer, but this one is always in 

 order), the bell was placed in my chamber, and 

 the battery and machine previously described 

 placed in the coldest part of the hothouse. One 

 pole of the battery was connected by a copper 

 wire with the bell, and from the bell the wire 

 was carried out to the machine and connected 

 with the end of the bar that was fastened, and 

 the thumb-screws connected to the other pole of 

 the battery. I then placed the screw on the 

 brass side so that it would come in contact with 

 the bar in case the thermometer should reach 

 40°, having previously found that the slightest 

 contact would complete the circuit and ring the 

 bell. After waiting about two weeks without 

 hearing anything from the apparatus, I was 

 startled from my chamber by the ringing of the 

 bell, and hastened out to find that a sudden and 

 severe change had lowered the temperature to 

 38° in the hothouse, and but for the increased 

 fire that was added the plants would have suf- 

 fered a bad chill, if not frozen before morning. 

 This has been kept in operation for two years, 

 and has several times saved my plants from total 

 destruction, or at least from great injury. By 

 adjusting the screw on the steel side of the bar 

 too great heat is easily detected. Since thor- 



