1902] MICROSCOPICAL JOURNAL 47 
MICROSCOPICAL NOTES. 
MroroscoPptcaL CEMENTS FOR FiLuip Cetis.—Mr C.F. 
Rousselet, has advocated for closing fluid mounts the use 
first of a coat of a mixture of damar and gold size, then ~ 
four thin coats of pure gold size, followed by a finishing 
coat of Ward’s brown cement at intervals of twenty-four 
hours. Further experience has shown that the addition of 
this last coat is a mistake, as by excluding the air, it pre- 
vents the oxidation, and consequently the hardening, of 
the gold size. The gold size therefore remains in a more 
or less semi-fluid state under the brown cement, which is 
not good. Pure shellac is not soluble in 24-per-cent 
formalin, and he therefore now closes fluid mounts as 
above, but with two coats of shellac between the damar 
and gold size, omitting the brown cement altogether, and 
hopes this will prove satisfactory. 
DIATOMS IN RHODE IsLAND.—In the Report of Inland 
Fisheries of this state is a list of the diatoms found in 
the waters over the clam, mussel and oyster beds at 
Wickford prepared by Henry W. Lothrop and Norman 
N. Mason. The food of these shell-fish is composed very 
largely of diatoms and localities rich in such forms of 
life usually abound in diatoms. For this reason state 
commissions have learned to regard the adaptability of 
waters to oyster propagation before going to the ex- 
_ pense of planting them. Of the various families of di- 
diatoms there were found 14 species of Cymbellea; 78 
Naviculea; 2 Gomphonemea; 2 Achnanthea; 11 Cocconi- 
dea; 35 Fragillaria; 12 Tabellaria; 33 Surirella; 17 
Chatocerea; 12 Melosirea; 11 Biddulphiea; 1 Eupodi- 
scea; 2 Heliopeltea; 17 Coscinodiscea,—a total of 248 
species. Copies can probably be obtained by Diatomists 
by addressing either of the authors at Providence, R. I. 
-‘Taat AwruL Drop or WaTER.—Public prints fairly 
