from their enjoyment, should be preserved. Nor was this often difficult to accomplish, for Venice gathered and dispensed through the agency of her vast shipping almost the entire luxuries of the known world, and the trade of her citizens was on this account eagerly courted by all nations.

At the close of the fifteenth century, Venice was in the meridian of her glory, at the very summit of her power. Nearly one hundred years before this, and her annual exports and imports to and from the lagune had amounted to the enormous sum of twenty-eight millions eight hundred thousand ducats; worth in those days many times what it would be at present; and even this was now prodigiously increased. Her dominions, too, embraced a wide range of territory; her riches were immeasurable, and her resources various and powerful. From the Po to the eastern boundary of the Mediterranean and the Don, stretched her long line of close-linked maritime stations; filled with the rich merchandise of all climes, enabling her to grasp almost the exclusive monopoly of trade throughout the European and eastern world. At home, her manufactures flourished a century in advance of the age. The culture of silk, introduced into the lagune from Constantinople, was most successfully prosecuted; and while its domestic use was interdicted to all save the high magistrates of the republic, her looms supplied the remainder of christendom with the most splendid specimens of this delicate and costly fabric. Her cloths, composed of the finest fleeces of Spain and England, were unrivalled in their beauty; and for the creation of her rich linens, the flax of Lombardy afforded ample materials. From the manufacture of gilt leather alone, one hundred thousand ducats were annually produced, while liquors, confectionery, and waxen tapers, the last of which were consumed to a great extent in the performance of holy services at Rome, increased and swelled the varied exports of the Ocean Queen. Costly mirrors from the giass-houses of Murano adorned the gorgeous palaces of Europe; and while the choicest luxuries of the age were profusely manufactured on every hand, in the laboratories of Venice were distilled and sublimated the rarest chemical preparations required either by medicine or the arts. The republic was not at this period more distinguished for its far-stretching commerce, the perfection of its manufactures, its internal strength, and the wide-spread dominions over which its sovereignty extended, than for its elegant literature, and the number of its citizens celebrated for their genius and learning. Among these, the names of Erasmus, Bembo, Gaunto, Navagero, Sabellico, and several others, are surrounded with associations and a fame of the most glittering character. Venice had now arrived at the epoch of her loftiest elevation, from which she gradually fell, until at last she was blotted out from the scale of nations. To follow her darkening fortunes, and trace out the causes of her fall, is not within our present purpose. Civilization and the arts, borne onward by the mighty science of printing, slowly traversed the slumbering states of Europe, awakening their dark-minded inhabitants to a knowledge of the resources within their reach; and as other nations, under the influence of this new light, arose from their long sleep, shook off the lethargy of ages, and started in the race of improvement, Venice, surrounded by ri vals, where she had before known no competition, commenced her downward course. Long and hard she struggled to maintain her brilliant stand as the first maritime power on earth, and many and fierce were the battles she fought to preserve her hard-earned conquests; but one after

another were wrested from her, until at last the islands of the lagune bounded her once vast sovereignty. The reformation spread its blazing light throughout Europe, and in its track followed the arts and sciences; barbarism fled at its approach, industry in its thousand branches was awaken. ed, new maritime states arose, and England, with all her energies and half her wealth applied to the extension of her commerce, and the increase of her naval strength, soon occupied that pre-eminent rank as a maritime power, which the arm and the policy of Venice had become impotent to retain.

And thus did her glory and strength fade away, while her citizens, too proud to engage in the commercial employment to which they owed all their former greatness, passed their lives in continual dissipation and the most enervating pleasures. Many of ancient families and noble blood, who had in this manner expended their entire fortunes, were reduced to abject want; and to these, begging licenses were officially granted by the state, and assuming a particular dress, with a hood drawn over the face to conceal their features, these noble beggars, under the name of the shamefaced, walked abroad and asked alms. That stern independence which for centuries had prevailed in the Venetian councils, elevating them beyond the reach of foreign influence, had departed; and with it had gone the honor, the dignity, and the virtues of her nobles and her citizens. The once mighty elements of her power had fled, her shipping had disappeared, her commercial interests were rapidly decaying, her once proud navy was no more, and the vast line of maritime stations she had formerly possessed, no longer acknowledged the sway of the Adriatic Queen. Stript of her strength, and regarded with contempt by kingdoms once her slaves, Venice, for a century before she was blotted from the catalogue of nations, slumbered on nerveless and inactive, unheeded by her neighbors, and be coming weaker and less formidable as every successive year rolled by; until at last, when Napoleon, holding the entire north of Italy in his grasp, presented himself before her, and haughtily demanded her surrender, the members of the grand council, carried away by fear, precipitately and without a struggle delivered their country into his hands. Three thou sand French soldiers at once marched into the city; every vestige of its independence was swept away, and in the division of territory that ensued, Venice was transferred to Austria; and on the 18th of January, 1798, the Austrian emperor assumed the control of his newly acquired domain. And in this manner did a maritime power, boasting an unbroken sway of more than eleven hundred years, sink into the grave of departed empires; and thus passed away that republic which had withstood the revolutions, battled with the shocks, and endured the changes of centuries.

We have called Venice a republic, and yet for many centuries before her fall, she hardly deserved the name. The doge was early invested with an irresponsible power, which on some occasions he exercised in the most despotic manner; and after the lapse of a few hundred years, the great body of the people ceased to exercise any important influence in matters of state. The prerogatives of the doge at length became dangerous to the interests of the nobility, and one after another were lopped off, until at last he became a mere puppet in their hands. Then commenced the reign of the Forty and the Ten; and finally was erected that fearful tribunal, the Grand Inquisition of State. These mighty arms of the government, acting with mysterious secrecy, and enforcing a code of laws

whose mildest provisions sanctioned poison and the dagger, upon even the suspicion of crime, wielded the destinies of Venice; and yet she preserved the name and outward semblance of a republic. Her citizens were seized, tortured, imprisoned, secretly tried and executed, and yet they boasted of freedom, the supremacy and purity of their laws, and of the wisdom of their institutions. But with all the imperfections and deformities of her political and moral system, sanctioning, as they unquestionably did, the darkest crimes, and the most terrible punishments, Venice, during the long line of centuries through which she flourished, stood in the front rank of nations, surpassed by few in the justice and humanity of her government, excelled by none in her knowledge of the arts and sciences, and in the perfection of her manufactures, and outstripping all in the magnitude of her commercial interests, and in the extent and splendor of her maritime power.

ART. II.-THERMOMETRICAL OBSERVATIONS AS CON. NECTED WITH NAVIGATION.

THE UTILITY OF THERMOMETRICAL OBSERVATIONS IN ASCERTAINING THE RELATIVE HEAT OF THE SEA-WATER FROM TIME TO TIME, TO DISCOVER THE PASSAGE OF A VESSEL THROUGH THE GULF STREAM, AND FROM DEEP WATER INTO SOUNDINGS, BANKS AND ROCKS, IN TIME TO AVOID DANGER, ALTHOUGH, OWING TO TEMPESTUOUS WEATHER, IT MAY BE IMPOSSIBLE TO HEAVE THE LEAD, OR OBSERVE THE HEAVENLY BODIES ;—AND ON PRESERVING VESSELS FROM LIGHTNING.

THE Merchants' Magazine has been so well conducted, and contains so much useful matter, which "comes home to the business and bosoms of mankind," that I am pleased by making it the vehicle of my remarks upon two of the most important subjects to which the attention of the nautical and mercantile community can be called.

The first head of my paper is the title of one which was read before the American Philosophical Society of Philadelphia, in the year 1790,* by the late General Jonathan Williams of the United States army,† whose

Trans., vol. II, p. 82.

+ I cannot permit this opportunity to pass without bearing testimony to the great me. rits of this excellent man. Like his relation Dr. Franklin, the tendency of his thoughts and actions was utility to his fellow creatures, to whom he also set an example of refined manners, uprightness of conduct, and good will, which can never be forgotten by those who had the happiness of his acquaintance. He entered the American army in the year 1801, and rose to the rank of colonel of engineers. It is to him that our country is indebted for the idea of the military academy at West Point, and for its organization, a task of no ordinary difficulty. His admirable, mild, but firm discipline, subdued tempers disposed to be unruly, eradicated bad habits from among the pupils, while he stimulated all to an honorable ambition to excel in their private deportment and in their official duties. His government was parental, and he was beloved as a father by the youth under his command. Science has seldom been applied more beneficially to forwarding the business of mankind, than in the instance of Mr. Williams' experiments,

attention was first called to the subject under consideration, from having made, in the year 1785, by the direction of his relation Dr. Franklin, the experiments mentioned in his description of the course of the Gulf Stream, an account of which was annexed to his "maritime observations,” addressed to the learned A. Le Roy of Paris,* and he determined to repeat these experiments in his future voyages. Accordingly, in one from Boston to Virginia, two from Virginia to England, three from England to Halifax, and four from Halifax to New York, he kept regular journals of the heat of the air and water at sunrise, noon, and sunset, and by consulting these, and the observations made at the dates written, together with the tracks of the ship's way, marked on the chart annexed, it will not only appear that Dr. Franklin's account of the warmth of the Gulf Stream is confirmed, but also that banks, coasts, islands of ice, and rocks under water, may be discovered when not visible, and when the weather is too boisterous to sound, with no other trouble than dipping the thermometer into the sea-water. His experiments also establish the following facts.

1. That the water over banks is much colder than the water of the main ocean, and it is more cold in proportion as it is less deep.

2. The water over small banks is less cold than that of large ones. 3. The water over banks of the coast, that is, those immediately connected with the land above water, is warmer than that over those which admit deep water between them and the coast; but still it is colder than the adjacent sea.

4. The water within capes and rivers does not follow those rules; it being less agitated, and more exposed to the heat of the sun, and receiving the heat from the circumjacent land, must be colder or warmer than that in soundings without, according to the seasons and temperature of the atmosphere.

5. The passage, therefore, from deep to shoal water may be discovered by a regular use of the thermometer before a navigator can see the land; but as the temperature is relative, no particular degree can be ascertained as a rule, and the judgment can only be guided by the difference. Thus, in August, Mr. Williams found the water off Cape Cod to be 58° of Fahrenheit, and at sea 69°; in October, the water off Cape Cod was 48°, and at sea it was 59°. This difference was equally a guide in both cases, though the heat was different at different seasons.

The chart and first journal of Mr. Williams, from Boston to Virginia, shows that the water on the coast of Massachusetts was at 48°; at sea, between the coast and the stream, 59°; in the Gulf Stream, at its edge, 67°; between that and the Virginia coast, further south, 64°, and in soundings on that coast, 56°.

and every navigator is under lasting obligations to him, for the knowledge of the means of securing their safety at times when the compass, the log, or the quadrant, nay, the organs of vision, avail them nothing.

* Trans. Amer. Philos. Soc., vol. II, p. 328.

The increased heat of the Gulf Stream, although doubtless familiar to navigators, it is believed was first noticed in print by Dr. Blagden in his paper on the subject, in the Transactions of the Royal Society of London for 1781. On the 30th September, 1777, the water was at 76 deg. of Fahrenheit, and eleven deg. above that of the sea, before the vessel came into the current. Mr. Strickland found this difference to be even greater, as will appear presently.

The second journal from Virginia to England, shows that the water on the coast of Virginia, in December, was at 47°; between the coast and the stream, 60°, and in the stream 70°; near the banks of Newfoundland the thermometer fell from 66° to 54°; passing these it arose again to 60°, and then continued a very gradual descent as he went north, till he struck soundings, when it was at 48°.

In Dr. Franklin's journal of November, 1776, the thermometer fell 10; near the banks and after passing them, it arose nearly to its former height. This agrees with Mr. Williams' journal nearly in the same place, made nine years afterward.

The third journal from England to Halifax shows the changes in the heat of the water, as he sailed over the banks and deep water alternately, with an accuracy that exceeded his expectation, the land appearing as the thermometer indicated an approach to it.

The journal from Halifax to New York, not only shows the variety of depths passed over, but indicates the inner edge of the Gulf Stream.

On the chart annexed to Mr. Williams' paper, the tracks of his several passages are marked, with the daily heat of the water, by which the variations on the approach to land may be seen at one view. The edge of the Gulf Stream is also traced, according to the experiments, as far as the banks of Newfoundland.

In addition to his journals, Mr. Williams has subjoined an account of some experiments on fish, (cod and halibut,) which show that their heat was 16° colder than the water at the surface, from which it may be supposed that the water at bottom is in proportion colder than that above: air 57°, water 52°, fish's belly 37°. Lat. 44° 52′; (July, 1790 :) air 57°, water 53°, fish's belly 37°.*

The difference of heat which marks an approach to land, he found to be 6 degrees in three hours run, and long before the vessel was near enough to be in danger. In a former voyage, it was found that near the coast, in very hot weather, the water at the bottom, in 18 fathoms, was 12 degrees colder than at the surface. This difference of heat is more remarkable in winter than in summer, for Captain Billings of Philadelphia, in a voyage to Oporto, in June, 1791, found that the water on the coast was 61°, and in the Gulf Stream 77°. By Mr. Williams' journals it appears that, in November, 1789, the water on the coast was 47°, and in the Gulf Stream at 70°.† Returning towards the coast of North America, Captain Billings discovered his passage across the Gulf Stream by a sudden fall in the mercury of 5° from noon to night; and about 5° further west, by a further fall, in the space of 8 hours, he discovered the coast, where he got soundings before he saw the land.

On the subject of the utility of the thermometer at sea, Captain Thomas Truxton, the well-known United States naval commander, wrote to Mr. Williams the following letter:

* These experiments were made by an officer of the British packet Chesterfield, Captain Schuyler, July 11, 1790. The preceding day, in another experiment, the temperature of the air was 57 deg., that of the belly of the fish 39 deg., water 52 deg., depth 46 fathoms. These results were communicated to Mr. Williams by Captain Schuyler.

+ Trans. Amer. Philos. Soc., vol. III, p. 194.