108 
them to have been, from intimate personal aequaintance, 
both with the men and with the country to which they 
were applied on precisely the same -evidence as is to be 
found in Canada, are at least entitled to be regarded as 
something more than ‘fancy sketches.’ 
‘‘T am, my dear Professor Dana, 
‘Very truly yours, 
ALFRED R. C. SELWYN. 
” 
““ (signed) 
Inquiry Regarding Fresh-water Pearl Fisheries. 
J eNCLOSE herewith a circular of queries that I am very 
desirous of having answered to assist in carrying out an in- 
vestigation in regard to the locations, yield and proper 
protection of fresh-water pearl fisheries in the United States. 
All correspondence on this subject should be addressed to 
meas follows: G. F. K., care of United States Com- 
mission of Fish and Fisheries, Washington, D. C. 
GEORGE F. Kunz. 
LIST OF QUESTIONS. 
The pearl-bearing mussels: 1. Nature of stream in 
which found, kind of bottom, character of water; 2. Geo- 
logical character of the district as to rock, soil, etc. ; 
3. General abundance of mussels; 4. Size, shape, and 
position of the mussel beds; 5. Local names of mussels; 
6. Habits of mussels; 7. Enemies and fatalities to which 
mussels are exposed, nature and extent of destruction by 
muskrats, hogs, freshets, etc.; 8. Size, shape, and color 
of mussels; 9. Species of mussels in which pearls are most 
common; ro. Proportion of mussels in which pearls 
occur; 11. Sizes, or other peculiarities, of shells in which 
pearls are found. The pearls: 12. Nature and origin of 
pearls; 13. Position in mussel; 14. Size, shape, and 
color of pearls; 15. Relative value of pearls of different 
sizes, shapes, and colors; 16. Markets for pearls; 17. 
Prices for pearls. The fishery: 18. Method of taking the 
mussels; 19. Description of apparatus used in taking 
mussels and in opening the shells; 20. Methods of ex- 
tracting the pearls; 21. Treatment of pearls when found; 
22. Utilization of mussels after extraction of pearls or 
after opening; 23. Principal occupations of mussel fisher- 
men; 24. Statistics of fishery in 1893: Fishermen, 
number; Boats, number, value; Apparatus, number, value; 
Pearls, number, value; 25. Statistics, complete or partial, 
for previous years; 26. Period when pearl fishing was of 
greatest importance in district; 27. History of origin 
and growth of fishery; 28. Kxhaustion of mussel beds, 
causes, rapidity; 29. Do exhausted beds become re- 
plenished, and in what time? 30. Is State protection of 
beds desirable or necessary? 
Psuedo-aurora. 
Tus phenomenon has again, this winter, been of un- 
usual beauty and brilliancy over lightsin this city. The 
following is an explanation of the occurrence: The phe- 
nomenon is not a shadow effect, as explained by Mr. Hazen 
in a number of last year’s Scence; neither has it any elec- 
trical significance, as has been indicated by several writers. 
It has a true light effect and consists of an apparent bright 
shaft of light extending upwards to the zenith over bright 
lights. If the lights are swung high it may also be seen 
extending from the light to the earth. It only occurs 
under certain atmospheric conditions, which are about 
as follows: Cold, cloudless nights, with but slight wind, 
if any, following upon an atmospheric humidity 
approaching saturation. Under these conditions, small, 
almost solid, flat, hexagonal ice crystals fall in a 
constant mist, glistening in a strong light, like particles 
of diamond dust. It is in the peculiar flat, light form of 
SCIENCE. 
VoL “Oat Wo. ee 
these crystals, associated with the manner in which they 
fall, that explanation of the phenomenon rests. 
Leaves falling from trees, during acalm, preserve, during 
the chief part of the descent, the horizontal position. This 
is found by careful observation to be alike true of the fall 
of the flat, hexagonal ice particles at the times when 
pseudo-aurora occur. The rays of light from the lamp or 
other brilliant light, striking the under flat surfaces of the 
crystals, are simply reflected to the eye of the observer; 
and the eye receives rays reflected from all particles of ice 
within the vertical plane through the eye and through the 
lamp or source of light, referring the grand final light 
effect to the vertical. 
That it is not of an electrical nature is evident in that 
some of the most brilliant shafts occur over bonfires, and 
when the moon is low in the horizon, on nights showing 
the aurora, it is seen to cause the same phenomenon. 
H. L. Bouiry. 
Fargo, North Dakota. 
Notes and Queries. : 
Rubus strigasus is rather common in Waterbury, Conn., 
but I have never found it bearing perfect fruit (except as no- 
ted below). The canes are quite as strong and thrifty as 
any found in northern New England, and plenty of flowers 
are produced, but rarely more than two or three drupelets 
in a berry ever mature. 
My observations extend over a period of more than 
thirty years. At present the plant is much more abundant 
than formerly, but the failure of the fruit to mature is the 
same as at first. Asking Dr. Asa Gray, at a meeting of 
the Botanical Section of the A.A.A.S., several years ago 
the cause of this, he remarked that ‘‘he should like to see 
the flowers ’’ before answering. 
Of course it is because they are not fertilized, but why 
are they not? Honey bees here, as further north, find the 
raspberry blossoms a rich source of honey, and any part 
they may take in the fertilizing process ought to be as 
effective here as in other sections The exception to this 
sterility makes the sterility still more singular. Along 
the ditches through some of our shallow peat bogs this 
red raspberry grows, sometimes, very rank and tall, and it 
is not rare to find, in September and October, the terminal 
portion of the year’s growth full of blossoms and perfect 
but unripe fruit. I have seen these berries fully grown, 
very large, but none quite ripe, though they probably do 
ripen in warm seasons. There is a cause for this failure 
of the summer crop, but what is it? I believe the cultivated 
species and varieties of the raspberry do as well here as 
anywhere. It is well understood that the failure of the 
first crop of red clover to produce many seeds is because 
the bumble-bees, the only insects that frequent its flowers 
for honey, are too few to transfer the pollen. 
This cannot be the case with the raspberry. It may 
be found that the honey-bee, wholly intent on gathering 
honey, neglects the pollen altogether and that the pollen 
gatherers prefer that of some other flowers found here. 
The interrelations between plants and insects are not all yet 
found out, but the suggestion made above may have no 
foundation in fact. 
Thirty years ago the farm yards and road sides in 
western Connecticut were white in the summer from the 
abundance of the flowers of the May weed (Warwfa Cotula). 
A few years later—but just when no one can tell, for it 
passed without observation—this plant disappeared en- 
tirely. For years not a single specimen could be found. 
It is now slowly reappearing, but not yet abundant. Over 
how large a part of the country this disappearance took 
place I cannot say, for my observations did not extend 
far beyond Waterbury and the adjacent towns. 
Here, as in numberless other cases, the ever-recurring 
why appears. Certainly no apparent cause banished this 
