DbCBMBEK 9, 1909. 



The Weekly Florists^ Review. 



89 



The "National" 



Differential Temperature Alarm 



Metallic 

 Thermometer"A' 



SizB— 8 inches bish, 4 inches vide, 2 inches deep. 

 Case made of cast aluminum, highly finished. 



This little instrument is an accurate, 

 fully tested thermometer showing the cor- 

 rect temperature at all times, and com- 

 bines a device which will ring a bell at 

 your bedside when the greenhouse gets 

 either too hot or too cold. 



The florist needs protection against the 

 overheating of his greenhouses as well as 

 a protection against cold, for which we 

 can highly recommend our type "A." 

 This device serves both purposes, and at 

 the same time indicates, as previously 

 stated, the actual temperature in his 

 greenhouse. 



We guarantee that actual results will 

 at all times be obtained. This device has 

 been subjected to the severest tests in our 

 laboratory, for over two yeavs, and at the 

 same time has given entire satisfaction, 

 under all conditions, to many users in the 

 trade. 



All you have to do is to set the point- 

 ers at the highest and lowest tempera- 

 tures you want, and- the thermometer will 

 do the rest. It will ring a good, loud 

 l)ell when either point is reached. 



Tins device saves all worry over trouble 

 from sudden temperature changes. 



Investigate it today. 



?^'fti 





A. T 





A"-35!>ti! 





/ 



Size— 4 inches in diameter, 1^ inch deep. Cadog made of Sheet Aluminum. 



A sudden cold snap, or a rapid thaw, may mean hundreds of dollars' 

 loss because your greenhouse gets too hot or too cold before you 

 realize the sudden change that has occurred. 



Protect yourself from such danger 



Our Differential Temperature Alarm is specially designed for florists' 

 use and is guaranteed to give absolute protection from the dangers 

 before stated. Set the pointers at the highest and lowest tempera- 

 tures desired and this device will positively ring a bell at your bed- 

 side when either point is reached. 



Over 2,000 of these instruments are now giving complete satisfac- 

 tion to florists throughout the country. 



It is constructed of the very best material available for the purpose, 

 and contains no complicated mechanism; hence serves its purpose a 

 lifetime. 



The pointers on face of instrument can be set so as to allow a dif- 

 ference between a iJossible increase or decrease of temperature of only 

 two degrees. All that is necessary is to change position of pointers by 

 loosening set screw in center so as to set the pointers or hands on face 

 of dial; then tighten said set screw. 



We also manufacture separate instruments; No. 1, to ring a bell 

 when the house gets too hot; No. 2, to ring a bell when the house gets 

 too cold. Of course, the most useful is the instrument illustrated 



above, whicli is a combination of both No. 1 and No. 2. 

 Let ua (lend you our catalog^ue of styles and prices. A postal will bring it 



National Clock & Electric Mfg. Co. 



2207 Pine Street 



SAINT LOUIS 



MISSOURI 



