12 



EXPERIMENT STATION RECORD. 



GERMINATION APPARATUS. 



The Nobbe clay disks arc used to some extent in a number of Scan- 

 dinavian seed-control stations, but where a large number of analyses 

 arc made either the Jacobsen or the Strokirk germination apparatus is 

 used. The former (fig. 1), constructed by C. P. Jacobsen, of Copenhagen, 

 consists of a large, square, metal tank, in which are placed narrow glass 

 plates (a). On these, round felt pieces are laid, which are connected with 

 the water in the tank by 

 means of small wicks. A 

 thick, loosely woven mat 

 is placed on the felt, and 

 on this again a piece of 

 filter paper, upon which 

 the seeds to be tested are 

 spread. A small glass 

 bell supplied with a nar- 

 row opening at the top, 

 to provide for circulation 

 of air, is placed over the 

 disks. The disks of felt 

 and the woven mat also 

 have holes in the middle 



to facilitate Circulation. Fhk l.-Jacobaen's seed-testing apparatus. 



A gas burner (c) heats the water in the tank, and to distribute the heat 

 more evenly a metal plate (b) rests loosely on small pillars, which sup- 

 port it a couple of inches above the bottom. 



This apparatus is easily regulated as to moisture and temperature, 

 is easily cleaned and examined, takes comparatively little room, and 

 gives very satisfactory and comparable results. The two pieces of 

 apparatus of this kind in use in the Danish seed-control station in 

 1896 had a capacity of 253 and 119 germination tests, respectively, at 

 a time. The tank, disks, glass plates, etc., were cleaned with boiling 

 water once every week, and the filter paper renewed every four days. 



The temperature of the bath ranges from 15 to 26° C, the temperature 

 during the night being 1(J to 17° C. Experiments made with a view of 

 finding a more favorable temperature have always given negative 

 results, as shown in the following series of experiments made by the 

 Danish seed control: 



Effect of constant ami variable temperatures on germination. 



Orchard grass 



Common rye grass 

 Italian rye gniss . . 



Number 



of sam- 

 ples. 



Viability at — 



18-25° C 



ST. 3 

 83.5 

 82.5 



Constant at 

 25° C. 



8C.3 

 81.9 

 82.1 



