BULLETIN OF THE BUSSEY INSTITUTION. 309 
The anthracite cinders were half burned bits of anthracite which 
had. fallen through the grate bars of a furnace fire. Each bit was 
freed from ashes and was coarsely powdered for the experiment. 
~ It was plain from the experiments that while the cinders contained 
no nitrogen available for the plants, they could supply an appreci- 
able quantity of phosphoric acid and some potash also. It may 
here be repeated that a certain small proportion of nitrogen de- 
tected in coal ashes in some of my earlier experiments was after- 
wards proved to have come from coal slack, that is to say particles 
of unburned coal which had fallen through the bars of a shallow 
furnace.* 
Since all the jars numbered 7 in this series of experiments 
gave better crops than those numbered 6, it appeared that lime 
was a useful addition to the sands. It is noteworthy further- 
more that while the plants grew fairly well in these sands proper, 
as is plainly evidenced by the Nos. 7 which had an abundant sup- 
ply of food, they failed to prosper in sand with which clays had 
- been mixed. 
The table relating to clays which has been printed on page 298, 
hardly conveys a just impression of the poverty of the crops. To 
do that, the miserable, sickly, crippled plants would have to be 
exhibited as they appeared in reality. To all appearance, the fine 
particles of clay actually clogged the pores of the plant roots and 
prevented the healthy development of the plants. So, too, in con- 
nection with the series of experiments reported on page 256 of 
vol. 1, there was another jar that contained 250 grammes of pipe 
clay and 230 grms. of Bussey peat. But only one plant grew in it, 
and that to a height of but six inches. It died more than a month 
before the crops in the other jars were harvested and weighed only 
0.08 grm. It had neither seed nor flower. In earlier experi- 
ments with mixtures of sand and clay the hurtful influence of the 
latter was still more apparent, as will appear from the following 
tables : — 
* See Bussey Bulletin, 1. 401. 
