a heated stove, with a view of purifying it. We have alfo the authority of Chaptal, of a ptyalism being excited, merely by inhaling oxygen gas, which was obtained from the red precip. (oxide of mercury.)-I hope my dear fir, you will excuse my lengthy and imperfect letter, and should be happy to hear your opinion upon this mode of exhibiting mercury. Since

cuticular abforption is denied us, how thall we explain the modus operandi of the mercurial ointments? Is it not by the heat of the body volatalizing the mercury, thereby creating a mercurial atmosphere, &c. Believe me to be

Dear Sir, your's respectfully,

P. W. LITTLE.

DR. J. R. Coxe.

Analysis of an Iron Ore, containing Titanium; by JAMES WOODHOUSE, M. D. Profeffor of Chemistry in the University of Pennsylvania.

THE

Philadelphia, Auguft 27th, 1807.

HE following experiments were performed upon an ore found in New Jersey, which I received from Dr. Mitchell of New York, in the year 1805, which was then fupposed to be an oxide of zinc, and which Count Bournon, one of the first mineralogists in Europe, has declared to be compofed of iron and titanium.

The specific gravity of this mineral is 5.28. When viewed, it has the appearance of black fpecks, the fize of duck fhot, furrounded by a red substance; and streaks of a white powder are difperfed through it, which confist of lithomarge or agillaceous earth. Looking at a specimen of it through a microscope, a small crystal of titanium, was seen adhering to it.

One hundred grains of it, reduced to an impalpable powder, and expofed one hour to the intense heat of a powerful air furnace, loft fifteen grains in weight, and from a brown, was

turned of a black colour.

Our hundred grains fubmitted to

heat, in the fame manner, with charcoal, produced a great number of finall globules of pure iron.

This metal can be separated from the powder, by a magnet. One hundred grains, boiled in aqua regia, was totally foluble in this agent, which proves it contains no filecious earth.

The pruffiate of potash, added to this folution, yielded a blue precipitate of pruffiate of iron, which, when dried, weighed three hundred grains. Now, if we divide this fum by six, it will give the quantity of metallic iron, contained in one hundred grains of the ore, which is fifty. A portion of lime was thrown down, from a folution of the mineral in aqua regia, by the oxalate of potafh. The carbonates of ammonia and potash, produced a copious, white and gelatinous precipitate.

One hundred grains, mixed with fix hundred of potash, were fubmitted to intense heat, in a black lead crucible, one hour. The part remaining in the crucible was powdered, boiled in water and filtered. Upon adding a fmall portion of muriatic acid to the water, a white precipitate was thrown down, which was fuppofed to be the titanium.

Upon collecting it, and mixing it with charcoal and spermaceti oil, it was exposed to the heat of a blacksmith's forge, when nothing was obtained, but a portion of a shining, black heavy substance, of the appearance of glafs. When the muriatic acid was added in excefs, to the filtered water, obtained by boiling the refiduum which remained in the crucible, in water, no precipitate was produced, until a folution of potash was added, to neutralize the acid.

The folution of the mineral in nitric acid, is very aftringent to the taste.

The ore appears to consist of iron, titanium, alumine, lime, and no filex.

Extract of a Letter from Profeffor SILLIMAN of Yale College, Connecticut, to MR. ROBERT HARE jun. of Philadelphia, on the Nitrous Oxide, Communicated to the Editor by Profeffor WOODHOUSE.

TH

HE following letter on this fubject, from Profeffor Silliman, of Yale College, Connecticut, has been put into my hands, by Mr. Robert Hare jun. of this city.

"Since my return from Europe, I have given the nitrous oxide a full and fair trial, and the refult has been fuch, as to confirm in the most fatisfactory manner, Mr. Davy's account of the effects of this wonderful agent. In my own cafe, after only two inspirations, I felt a momentary loss of distinct thought,; then fenfations of pure and vehement delight, tingling through every fibre of my frame, to the extremities of my toes and fingers, then, after failing in an attempt to express to my friends by articulate words, the pleasure I felt, I demonstrated it by leaping up and down, stamping on the floor, and loud convulfive laughter.

One of our gravest citizens, a man of thirty-eight or forty years of age, was made to caper about like a monkey, with all the extravagant gestures of a tragedian, and the grimaces of a harlequin. Some effect was produced upon all that breathed the gas and the full effect was manifested in fix instances out of eight. One of these took place before many spectators, and was fo marked as to banish every doubt. The reason that these experiments have not generally fucceeded is, that the gas has not been employed in fufficient quantities. Six or eight quarts breathed into, and out of a filk bag, will always produce the effect.”

ERRATA.

Page 136, in Dr. Rush's communication, last line, for and medicines" read “ and tonic medicines."

Page 179. in Dr. Woodhouse's communication, line 2, 'for "dephlogisticated air," read "dephlogisticated nitrous air.”

MEDICAL MUSEUM.

VOL. IV....No. IV.

A few Words more against Cutanecus Absorption. By J.C. ROUSSEAU, M. D. Phyfician to the Philadelphia Difpenfary.

July 19th 1807.

L

ONG ago have I promised, and oftentimes fince determined, to pursue my inquiries upon Cutaneous Abforption; but convinced by the evidence of the numerous experiments corroborating the new doctrine that I have established, I could but fmile, and recollect how much time, and how many useless arguments were wasted by one of my preceptors, to demonstrate that "a straight line was the shortest that "might be drawn between two given points."

*

Much has been and is daily faid in fupport of this supposed function of the skin: fuperftition and prejudices, religious advocates of old erroneous doctrines, too often receive the affiftance of pride and obftinacy; arguments which have been com

* See my Inaugural Differtation, 1800. Philadelphia. 2. Henry P. Dangerfield, Inaugural Differtation, 1805. . 3. Jofeph Klapp, Inaugural Differtation, 1805.

E e

pletely refuted, are again and again brought forward, backed by fome experiments, which when confidered aftentively, however deferving of notice they may appear at first view, cannot in any way afford the least help to that falling doctrine.

It is indeed amufing to liften fometimes to a number of facts feriously related, and gravely explained, to fhoulder up such an erroneous opinion of the old fchool, as if the faculty was to lofe by its fall, any of its privileges to befmear the body of a faithful patient, who seldom dares to ask for an account of the modus operandi, and whom it would be easy to fatisfy, (if it was neceffary) by only fubftituting the much more elegant and scientific word Sympathy.

"Pray fir," was asking me once a thoughtful gentleman, rubbing his fnuff-box, after having quartered his gold-headed cane under his arm, "how do you account Sir," paufing to load his nose, " for this fact-that- failors having no fresh water on board, quenched their thirst by plunging their bodies in, and wetting their clothes with fea water."

Have you feen it, Sir, replied I, with an inquifitive look? "I cannot-say so."

Nor I either however, as I am not difpofed at prefent to deprive you of the benefit of authorities, I will grant the fact, (which by the by, if it was put in practice, would save a great deal in many respects) if you dispense me with its explanation until you have yourself accounted for the following observations of the fame nature, and established, not by the authority of a few, but by general felf-experience.

How often you and I, and many others have experienced a great thirst in the night, and not being able to find any water