JANUARY 11, 1884.] 
capital letters is well enough, even though the names 
have been derived from proper names; but, if we say 
-it is a choice specimen of Begonia Rez, the case is 
different. The word ‘begonia’ now becomes a part 
of the scientific name of a species of plant. In the 
same manner the stately magnolia may be Magnolia 
glauca or M. grandiflora. 
Science does not use emphatic type for the scien- 
tific names of genera or species, and doubtless for 
good reasons. I should like to learn what views the 
editor and other authorities in scientific nomenclature 
hold on the above subject. Byron D. HALSTED. 
- New York, Dee. 31, 1883. 
[We do not agree with our correspondent in his 
estimate of the value of the scientific names of plants 
and animals. They are a simple convenience, and 
have no higher value; and the use of italics for their 
proper mission — that of emphasis, or as catch-words 
— is lost if the page bristles with italics having other 
meaning. ] - 
The skidor in the United States. 
In Science, No. 44, mention is made, in Norden- 
skidld’s account of the Greenland inland ice, of the 
‘skidor,’ or Norwegian snow-shoe. 
teresting to your readers to know that it is the snow- 
shoe most commonly used in Colorado. It is much 
preferred to the Canadian or web snow-shoe, and in 
the mountains in winter is often the only means of 
getting about from place to place —as from the mines 
on the mountains to the towns, and from one small 
mining town to another— when there is not enough 
travel to keep a road open through the deep snow. 
I know of one case in which a daily mail is carried 
twenty-five miles on snow-shoes; two men having the 
route, each making a single trip in a day, but going - 
in opposite directions. The motion can hardly be 
called ‘running,’ as it is in the footnote on p. 7387, 
as the shoes are not lifted from the surface of 
the snow at all, but slid forward at each step, the 
foot being raised slightly at the heel as in commen- 
cing a step in ordinary walking. The shoes that I 
have seen are from six to eight feet long, and about 
four inches wide. A pole about seven feet long is 
used as a guide and support, especially in sliding 
down hill, when a tremendous pace is often attained 
on a long slope. E. R. WARREN. 
Colorado Springs, Jan. 1. 
Standard thermometers. 
In your editorial in this week’s Science you quote 
the report of the chief signal-officer of the army, im- 
plying that a sensible difference exists between the 
theoretical standard thermometer adopted by this 
observatory and that of the International committee 
of weights and measures, and that the signal-service 
of the army has adopted a new standard thermome- 
ter more nearly agreeing with the latter. 
I should be very greatly obliged to the chief signal- 
officer if he will anticipate the regular course of pub- 
lication of. the scientific work of his office, and give 
to the scientific public the results, at least, of the work 
from which it is concluded that the signal-service of 
the army has reached a nearer approximation to the 
Standard thermometer of the International commit- 
tee. 
I have no doubt that there is a small difference be- 
tween the standard air thermometer and the particu- 
lar mercurial standard adopted by this observatory 
as its practical representative, at points distant from 
the freezing and boiling points; but, as our own stand- 
It may be in-: 
SCIENCE. 33 
ard has never been compared with any air standard 
in the possession of the signal-service of the army, I 
shall be quite interested to see the work by which it 
is concluded that there exists a sensible difference 
between the two. LEONARD WALDO. 
Dec. 31, 18838. 
Romalea microptera. 
In 1879, in Alabama, I had many opportunities for 
observing the habits of the ‘lubber grasshopper;’ and, 
if my memory serves me, my observation showed that 
the hissing referred to by Capt. Shufeldt (Science, 
ii., 813) is due in large part to the forcible expulsion 
of air from the thoracic spiracles. It was always no- 
ticed on the occasions referred to by him, but at no 
other time. A. YT: 
Synchronism of geological formations. 
I cannot agree with Professor Heilprin in the line 
of argument adopted in his letter to Science of Dec. 
21, based, as it mainly is, on the assumed non- 
occurrence of ‘evidence of inversion.’ Professor 
Heilprin asks, ‘‘ Why has it just so happened that a 
fauna characteristic of a given period has invariably 
succeeded one which, when the two are in superposi- 
tion all over the world (so far as we are aware), in- 
dicates precedence in creation or origination, and 
never one that can be shown to be of a later birth ?”’ 
In reply I would say, that some years previous 
to Professor Huxley’s address on this subject, Bar- 
rande, in his ‘Systeme Silurien de la Bohéme,’ had 
shown such evidences of inversion to exist in the 
Silurian formation of Bohemia; and though many 
‘geologists and paleontologists disagreed with Bar- 
rande at that time, as to his theory of ‘ colonies’ by 
which to account for the facts, yet none could dis- 
pute the facts cited by him. If we now turn to the 
old red sandstone of Scotland, we find still further 
evidences of inversion of like kind; for, while the 
crustacean genus Pterygotus, common to both the 
upper Silurian and lower old red sandstone, has been 
recently found also high up in “the middle series of 
this formation, the carboniferous limestone shells, 
Productus giganteus, P. punctatus, Spirifer lineatus, 
and others, have been found in the old red sandstone 
far below the fish genera Pterichthys and Holopty- 
chius, so characteristic of: the upper old red division. 
Though there appears to be no reason why such in- 
stances of inversion should not have occurred over 
and over again, one can readily understand why, 
through the imperfection of the geological record, 
and the comparatively small fraction of the earth’s 
surface which has been systematically examined, their 
occurrence is almost unknown. 
With reference to the doctrine of migration, I judge, 
that, from Professor Heilprin’s argument, we look at 
the matter from two different stand-points. He ap- 
parently takes no account of the generally accepted 
view of biologists, that, while organic development 
has been closely similar in all parts of the world, the 
rate at which it proceeded has varied within the 
widest limits, even in adjacent regions. I cannot 
help looking on the various formations as the records 
of that development; and, judging of the past distri- 
bution of life on the earth from what we at present 
see before us, I am forced to believe that identity of 
organic contents in widely separated strata, instead 
of being evidence of chronological contemporaneity, 
is exactly the reverse. 
Instead of encroaching further on your valuable 
space, I would refer to Prof. A. Geikie, who, in the 
current issue of the Encyclopaedia Britannica (9th 
