Scientific Intelligence. 
209 
induced also to believe, with our author, that the activity of Malaria may very much 
depend upon this process. The remarks and observations which Mr. Addison has 
made upon diseases as they appear in tropical climates, certainly furnish a powerful 
statement in favor of the view he has taken. We earnestly recommend this subject 
to the profession of which Mr. Addison is a member ; the conclusion he has drawn 
are, that all those places where the radiation, of caloric goes * on with rapidity , will 
be found subject to great vicissitudes of temperature, to fogs, heavy dews, and other 
noxious precipitations from the air, whereby they are rendered cold, damp , and of tea- 
time* extremely unhealthy j white ceteris paribus those situations where the terrestial 
radiation is diminished will be proportionally warm , drier , of a more agreeable tern* 
perature , and more healthy 
3. — Brittle Pens. 
. To the Editor of Gleanings in Science. 
Sir, 
If you have ever experienced the incon- 
venience of having your pens opened by the 
hot winds ; you will readily grant the uti- 
lity of some plan to prevent such an an- 
noyance. Should you consider the accom- 
panying very rough sketch of an inkstand as 
deserving of notice as I have found the 
original useful, you will probably when 
convenient give it a place in your “ Glean- 
ings." 
The invention is not my own, but sug- 
gested by plans adopted by two friends. In 
one the floating wood was wanting, and the 
pens became too wet ; in the other the ink 
holder was separate, which produced occa- 
sional inconvenience : by combining both I 
think the idea is improved. 
I remain, 
Your obedient servant, 
22d May 1829. X. Y. Z. 
For want of something better I have been 
obliged to use a common tumbler ; but the 
whole might be greatly improved in appear- 
ance. 
a. a. a. a. The tumbler filled half fullwith 
water. 
b. b . A piece of wood a little less than the 
circumference of the tumbler, floating in the 
water to support the pens. 
c. The inkholder. 
d. d. The cover with holes to admit the 
pens and inkholder. 
e. A bird’s eye view of the cover. 
4 ,—Royal Clarence Sextant • 
The advantage to he gained by the royal Clarence sextant will never counterba- 
lance the expense of such an instrument, when it is in the power of every man who 
knows any thing of navigation always to calculate the angle which the objects 
must subtend at certain distances when lie is approaching one of them on a line 
perpendicular to their distance. It is only in such cases that the royal instrument 
can be useful, and then not more so than the common quadrant. How easy is it 
for a commander, knowing that a light-house and flag-staff are N. by E. and S* 
