HYD 
llYD 
Heat. 
95 
grains 
of spirit 
to 100 
gr. of 
water. 
90 
grains 
of spirit 
to 100 
gr. of 
water. 
85 
grains 
ofspirit 
to 100 
gr. of 
water. 
80 
grains 
ofspirit 
to 100 
gr. of 
water. 
75 
grains 
of spirit 
to 100 
gr. of 
water. 
70 
grains 
of spirit 
to 300 
gr. of 
water. 
65 
grains 
ofspirit 
to 100 
gr. of 
water.- 
6o 
grains 
of spirit 
to 100 
gr. of 
water. 
55 
grains 
of spirit 
to 100 
gr. of 
water. 
50 
grains 
of spirit 
to J00 
gr. of 
water. 
30 :l 
.94447 
.94675 
.94920 
.95173 
.95429 
.95681 
.95944 
.96209 
.96470 
.96719 
35 
94249 
94484 
94734 
94988 
95246 
95502 
95772 
96048 
96315 
96579 
40 
94058 
94295 
94547 
94802 
95060 
95328 
95602 
95879 
96159 
96434 
45 
93860 
94096 
94348 
94605 
94871 
95143 
95423 
95705 
95993 
96280 
50 
93658 
93897 
94149 
94414 
94683 
94958 
95243 
95534 
95831 
96126 
55 
93452 
93696 
93948 
94213 
94486 
94767 
95057 
95357 
95662 
95966 
60 
93247 
93493 
93749 
94018 
94296 
94579 
94876 
95181 
95493 
95804 
65 
93040 
93285 
93546 
93822 
94099 
94388 
94689 
95000 
95318 
95635 
70 
92828 
93076 
93337 
93616 
93898 
94193 
94500 
94813 
95139 
95469 
75 
92613 
92865 
93132 
93413 
93695 
93989 
94301 
94623 
94957 
95292 
80 
92393 
92646 
92917 
93201 
93488 
93785 
94102 
94431 
94768 
95111 
Heat. 
45 
grains 
of spirit 
to 100 
gr. of 
water. 
40 
grains 
of spirit 
to 100 
' gr. of 
water. 
35 
grains 
of spirit 
to 100 
gr. of 
water. 
30 
grains 
ofspirit 
to 100 
gr. of 
water. 
25 
grains 
of spirit 
to 100 
gr. of 
water. 
20 
grains 
ofspirit 
to 100 
gr. of 
water. 
15 
grains 
of spirit 
to 100 
gr. of 
water. 
10 
grains 
of spirit 
to 100 
gr. of 
water. 
5 
grains 
ofspirit 
to 300 
gr. of 
water. 
30° 
.96967 
.97200 
.97418 
.97635 
.97860 
.98108 
.98412 
.98804 
.99334 
35 
96840 
97086 
97319 
97556 
97801 
98076 
98397 
98804 
99344 
40 
96706 
96967 
97220 
97472 
97737 
98033 
98373 
98795 
99345 
45 
96563 
96840 
97110 
97384 
97666 
97980 
98338 
98774 
99338 
50 
96420 
96708 
96995 
97284 
97589 
97920 
98293 
98745 
99316 
55 
96272 
96575 
96877 
97181 
97500 
97847 
98239 
98702 
99284 
60 
96122 
96437 
96752 
97074 
97410 
97771 
98176 
98654 
99244 
65 
95962 
96288 
96620 
96959 
97309 
97688 
98106 
98594 
99194 
70 
95802 
96143 
96484 
96836 
97203 
97596 
98028 
98527 
99134 
75 
95638 
95987 
96344 
96708 
97086 
97495 
97943 
98454 
99066 
80 
95467 
95826 
96192 
96568 
96963 
97385 
97845 
98367 
98991 
HYDROPHILUS, in natural history, a 
genus of insects of the order Coleoptera. 
Antennae clavate, the club perfoliate ; feel- 
ers four, filiform ; the hind legs are formed 
for swimming, fringed on the inner side, 
and nearly unarmed with claws. The in- 
sects of this genus, like those of the Dytis- 
cus, which see, are inhabitants of ponds 
and stagnant waters, where they swim 
with much dexterity, turning round with 
great velocity ; they fly abroad by night in 
search of other waters. The males are dis- 
tinguished from the females, by having a 
homy concave flap or shield on the fore 
legs, near the setting on of the feet; the 
hind legs are peculiarly fitted for their aqua- 
tic situation, being furnished on the inner 
side with a series of long and close-set fila- 
ments, resembling a fin, by which they are 
enabled to swim with great ease. The lar- 
va remain about two years and a half be- 
fore they change into pupae, forming a con- 
venient cell, and secreting themselves in 
some bank. They are very voracious, and 
destructive to the more tender aquatic in- 
sects, worms, and young fish, which they 
seize with their forked jaws, and destroy 
by sucking out their juice. There are up- 
wards of thirty species. The principal Eu- 
ropean species is the H. piceus, water- 
clock, which is not uncommon in our own 
country. The female of this species affords 
an example of a faculty, which seems to be 
exercised by no other insect of this order, 
viz. that of spinning a kind of web, or flat- 
fish circular case of silk, which it leaves 
floating on the water, and in which it de- 
posits its eggs. This case, says Dr. Shaw, 
is terminated on its upper surface by a 
lengthened conical process, resembling a 
horn, of a brown colour, and of a much 
stronger nature than the case itself, which 
is white. The larv®, as soon as hatched, 
make their escape from the envelopemeht 
