Fixation of Free Nitrogen hij the Lower Green Plants. 431 
tion of free nitrogen, or whether they effect a symbiosis similar to 
that which exists between papilionaceous plants and the nodule- 
forming microbes, is a problem which still awaits investigation, and 
this will doubtless be forthcoming in due course. Meanwhile, the 
results of the experiments which arc here briefly set forth are of the 
greatest interest, and serve to add another link to the chain of facts 
which are so profoundly modifying our views concerning the nutrition 
of plants. 
Since the foregoing was in type, I have been favoured with a 
letter from Dr. J. H. Gilbert, F.R.S., in which he states that when 
at Halle last year, Hellriegel told him that they had been experi- 
menting on this subject ; and more recently he has sent Dr. Gilbert 
some account of their results. In 1889 they filled a series of glass 
jars with sterilised sand ; some were left without infection, some 
were infected with the watery extract of soil ; some were excluded 
from light, and others exposed to light. In the dark there was, 
neither without nor with microbe-seeding, more than a mere trace 
of either growth or gain of nitrogen ; but in the light there was, 
with microbe- seeding, considerable growth and considerable gain of 
nitrogen. Other somewhat similar experiments were also made, 
with similar results. The growth was chiefly of Alg«e. 
Professor Hellriegel concludes that certain Alg?e, and certain 
other low forms, do fix free nitrogen ; and in answer, ^to Dr. Gilbert’s 
inquiries, he gives it as his opinion that the action may be of some 
importance in the origination of soils, but probably not in soils 
under actual cultivation. 
W. Fueam. 
RECENT AGRICULTURAL INVENTIONS 
The subjects of Applications for Patents from March 14 to 
Ju7te 10, 1892. 
N.B.-^Wliere the Invention is a communication from abroad, the name of 
the Inventor is shown in italics, between parentheses, after the name of the 
applicant. 
Agricultural Machinery and Implements, &o. 
A^Hcation. Applicant. Title of Invention. 
(Year 1892) 
6133 Peekins, j. E. S. . . Hay-making machines. 
6454 Panton, J. R. . . Automatic self -feed for threshing machines. 
6494 Wahbuhton, J. S. . Machine for digging potatoes. 
6649 4So\nrs{Merccr, Canada) Sheaf binders. 
6691 Staynek & Robebts , Spades. 
VOL. 111. T. S. — 10 
G G 
