Juty 13, 1899] 
NATURE 259 
Essex Institute, Salem, vol. xxix.). These “ wash-plains” or 
stream deltas and fans constitute a very important feature in the 
Pleistocene deposits of the region. They form the lowlands on 
which the greater number of towns and villages are built. To 
the early settler, they offered flat ground free from the boulders 
which are strewn over the uplands ; and they yield vast stores 
of gravel and sand in fairly definite positions. Representing the 
morainal deposits of a retreating ice-lobe, they comprise the 
materials spread out at successive stages by streams and rivers 
which issued from the ice ; and these deposits vary according to 
their original relations to the frozen mass. Hence the coarse 
gravels and the finest sands may be looked for in particular 
areas. No definite relations to sea-level are found among the 
various wash-plains. It is noticed that temporary lakes were at 
times produced by the local presence of blocks of ice ; and it is 
‘pointed out that the retreat of the ice from the area was so 
recent that the general form of the deposits and most of their 
details remain unaltered. Owing, however, to the decay of 
some of the basaltic and other stones, the surface of the ground 
has been somewhat lowered. 
Herr A. WEIGEL, of Leipzig, has acquired the last two 
remaining copies of Kiitzing’s Zabulae Phycologicae, in 19 
vols., with 1900 coloured plates, which he offers for sale at 
2400 m. (Kiitzing’s own copy) and 2000 m. respectively. 
Messrs. DuLAU AND Co., of Soho Square, have issued a 
catalogue of botanical works, consisting entirely of works on 
Phanerogamia, which are arranged alphabetically in their natural 
orders. The same firm forwards also a catalogue of books and 
papers on British botany, 
Bulletin 168 of the Cornell University Agricultural Experi- 
ment Station is devoted to an account, by Prof. G. F. Atkinson, 
of three species of Fungi which he regards as valuable from an 
esculent point of view, Cofrinus comatus, C. atramentarius, 
and C, mzcaceus, with abundant illustrations. 
Dr. F. SCHLEICHERT has an interesting note, in a recent 
number of the Waturwissenschaftliche Wochenschrift (June 
25) on the observation of phenomena of vegetable physiology in 
the winter. Many of them, especially those connected with 
the supply of nutrition, may be followed nearly equally well at 
that period of the year as in summer. 
Dr, L. O. Howarp has published an account or the 
principal insects affecting the tobacco-plant in America in the 
Year-book of the Department of Agriculture for 1898. Although 
the plant is said to have no enemies peculiar to itself, it suffers 
from the attacks of many omnivorous Lefidoplera, especially 
Sphinges and Noctuze; and from those of various Coleoptera, 
Hemiptera, &c. 
WE have received parts 10-12 (published in 1898) of the 
second volume of a journal called Zavowva, published by the 
National Society of Agriculture of Brazil. Among the mis- 
cellaneous contents which fill the magazine, we find a coloured 
plate of the imago and pupa of a butterfly (He/écontus eucrate, 
Hiibn.); illustrated articles on a formidable internal parasite 
(Anchylostoma), and on the history of the wheat-plant; a 
portrait of the late Prof. Aimé Girard ; notices and figures of 
Eleusina coracano and indica (forage-plants) ; and much agri- 
cultural and statistical information, primarily, of course, of 
local interest, 
THE first number of Le Mors scientifique et tndustriel—a 
monthly synopsis of scientific information—has been received. 
To some extent, the new periodical resembles Sczence Abstracts, 
but it contains more abstracts of engineering papers, and less cf 
scientific investigations. The abstracts are concise, comprehen- 
NO. 1550, VOL. 60] 
sive as regards nationality, and well printed ; they should, there- 
fore, be of real service to French readers interested in the 
progress of pure and applied science. 
A CAREFUL investigation of tautomeric compounds, 2.é. sub- 
stances which react as though each possessed more than one 
molecular structure, though only represented by ove substance, 
has revealed in a few cases the actual existence of the different 
structural forms. A very interesting example is furnished by 
diacetylsuccinie ester, which has lately been studied by Prof. 
Knorr, At the time of its discovery it was regarded as a single 
distinct individual, having the formula 
CH,.CO.CH . CH.CO.CH; 
coor oor 
According to Knorr the presence of the other structural isomers 
has been overlooked from the fact that, though not the most 
stable relatively, the original compound has the highest melting 
point, and, being the least soluble, has crystallised most readily 
from solution. Knorr predicted some time ago the existence of 
seven isomeric compounds, not including optically active forms, 
andof these he has already succeeded in preparing five, whilst 
he considers it very probable that the two missing members 
will be found. These will be represented by the following 
formulae :-— 
CH,.CO.CH.COOR 
| 
CH;.CO.CH.COOR 
Keto-form f 
representing two representing three 
inactive forms. cis-trans-forms, 
CH,.C(OH) : C.COOR 
CH,.CO.CH.COOR™ 
Keto-enol-form 
representing two 
inactive forms. 
CH,.C(OH) : C.COOR 
| 
CH,.C(OH) : C.COOR 
Enol-form 
A RECENT issue of the Zvansactions of the Oxford University 
Junior Scientific Club contains a valuable account, by Mr. A. F. 
Walden, of the condition of dissolved substances in solutions 
other than aqueous. The experiments of Carrara have shown 
that solutions in methyl alcohol exhibit a progressive ionisation, 
and that the independence of the ions is as clearly marked as in 
the case of aqueous solutions. Tessarin has also shown that the 
molecular lowering of the freezing point of formic acid brought 
about by the chlorides and bromides of the alkali metals is 
abnormally high, showing that this solvent also behaves like 
water. Recent experiments by Franklin and Kraus have shown 
that liquid ammonia acts as a dissociating solvent. In reference 
to the hypothesis of Nernst that the dissociating influence of 
a solvent is related to its dielectric capacity, it is to be remarked 
that the dielectric constants of water, methyl alcohol, acetone, 
formic acid, and ammonia are all high. It is pointed out also 
that these solvents, with the possible exception of acetone, are 
characterised by having ‘‘associated” molecules. On the 
whole, therefore, it may be said that the phenomena which it is 
attempted to represent by the hypothesis of electrolytic dissoci- 
ation are not peculiar to aqueous solutions. They are, so far as 
experimental evidence is available, found to be characteristic of 
solutions of salts in other solvents possessing high dielectric 
capacities and complex or associated liquid molecules. Accord- 
ing to Thwing, the dielectric capacity is both an additive and a 
constitutive property. It increases as the temperature is lowered. 
The factor of association, according to Ramsay and Shields, also 
increases as the temperature is lowered. These facts have all to 
be considered in dealing with solutions and in comparing 
ionisation determinations made by different methods, Thus we 
have some explanation of the observation that the degree of 
ionisation of metallic salts dissolved in methyl or ethyl alcohol 
is uniformly less when estimated by the boiling point method 
