10 



PENNSYLF/1NIAN SPORES OF ILLINOIS 



coal for the second phase of the maceration 

 process depends upon the rank and physical 

 nature of the coal. Banded ingredients of 

 Illinois coal beds do not oxidize at the same 

 rate. Experiments have shown that in 

 general the order of oxidation for a given 

 coal sample is vitrain, clarain, durain, and 

 fusain. The time necessary to oxidize dif- 

 ferent coal beds varies considerably. The 

 maximum and minimum time generally 

 required to complete the oxidation phase of 

 the maceration process on non-weathered 

 Illinois coal using a two-to-one Schulze's 

 solution is as follows : 



McLeansboro coals 6 to 50 hours 



Carbondale coals 12 to 100 hours 



Tradewater coals 36 to 140 hours 



Caseyville coals 48 to 206 hours 



The longest oxidation time required for 

 any Illinois coal was that of the Reynolds- 

 burg bed of Caseyville age. The length of 

 time necessary to oxidize coal may be 

 shortened by increasing the temperature of 

 the mixture, or by increasing the strength 

 of the solution. 



Coals while still in Schulze's solution can 

 be tested to determine whether or not they 

 are ready for the second phase of the macera- 

 tion process by placing a small portion of 

 the partially oxidized coal in a beaker and 

 washing it free of acid. The coal is then 

 covered with a 10 percent solution of KOH ; 

 if a heavy brown liquid forms (release of 

 the humic matter), a drop of this liquid is 

 placed on a glass slide and examined 

 microscopically for spores. If spores are 

 present in abundance, the maceration is 

 ready for the second phase. The remainder 

 of the partially oxidized coal sample in 

 Schulze's solution should be washed with 

 H 2 until a pH of approximately 7 is 

 reached. This may be accomplished either 

 by siphoning or decanting with several 

 changes of H 2 0. 



The second phase of the maceration may 

 be expressed in the following manner : 



(Soluble portion (salts of 

 Partially oxidized 1 humic acids) 



coal + H 2 + KOH \ Insoluble portion (preserved 

 ( botanic ingredients) 



The KOH solution usually used is 10 

 percent, but it is preferable to use as weak 



a solution as possible. Two or three percent 

 solutions have given creditable results. The 

 second phase of the maceration process is 

 completed when abundant spores are pres- 

 ent. The time necessary for the second 

 phase may vary from 15 minutes to more 

 than 12 hours. As shown in figure 1, the 

 soluble humic matter is washed from the 

 residue which is then ready for sizing. 



The coal residue is divided into two frac- 

 tions by screening with a standard 65-mesh 

 Tyler screen, the openings of which are 

 0.0082 inch or 210 microns. The filtrate 

 of this screening process, the minus 65- 

 mesh material, contains the small spores 

 and prepollens. Some of the larger spores 

 which are included in this filtrate material 

 may be small megaspores. After each 

 screening, the screen should be carefully 

 cleaned to avoid possible contamination 

 from one screening operation to the next. 



The spores contained in the minus 65- 

 mesh screenings vary from light or pale 

 yellow to dark brown. It is necessary to 

 stain the material to obtain good photo- 

 micrographs and to study the minute struc- 

 tural details of the spore coat and append- 

 ages. The staining process is simply a 

 matter of covering the residue with a con- 

 centrated aqueous solution of safranine Y 

 (other stains may be used) from 10 to 12 

 hours. Warming the staining solution two 

 to three hours is usually sufficient to stain 

 the residue. When the staining process is 

 completed, the surplus liquid is drained or 

 decanted off and the residue dehydrated with 

 alcohol* as shown in figure 1. For glycerin 

 jelly mounts, excess stain may be removed 

 by several changes of H 2 0. For diaphane 

 mounts, the alcohol solution is mixed with 

 a 50-50 solution of absolute alcohol and 

 diaphane solvent, followed by pure diaphane 

 solvent. The final mounting is accom- 

 plished by draining off the excess pure di- 

 aphane solvent, and mixing a portion of the 

 residue with diaphane and mounting. Com- 

 mercial diaphane is somewhat thin for 

 mounting spores, and best results have been 

 obtained by exposing the mixture of diaphane 

 and residue to air, which slightly thickens 

 the diaphane. The portion of the residue 

 not used in preparing slides may be saved 



