Marcet

Faraday lived his entire life in what is now greater London. The son of a blacksmith, he had no formal education beyond the rudiments of reading, writing, and arithmetic. Apprenticed to a bookbinder at the age of 13, Faraday educated himself by reading virtually every book that came into the shop. One that particularly impressed him was a textbook, Conversations in Chemistry, written by Mrs. Jane Marcet. 

Fortunately for a poor, would-be chemist like Leblanc, France s aristocratic passion for the physical sciences crossed economic, social, and political borders. Intellectuals such as Rousseau and Diderot cultivated the sciences with enthusiasm and compiled encyclopedias and dictionaries of natural substances. Local academies and institutes in the far-flung provinces sponsored chemical studies. Crowds flocked to hear chemists lecture and to watch their flashy laboratory demonstrations. Even the future revolutionary, Jean-Paul Marat, experimented with fire, electricity, and light and tried—in vain—to become a member of the Royal Academy of Sciences. In America, Benjamin Franklin abandoned his printing and publishing business for physics, and in England his friend Jane Marcet wrote Mrs Marcet s Conversations in Chemistry for women and working-class men. 

Marcet, Jane. Conversations on Chemistry. 6th ed. 2 vols. London Longman, 1819. 

Marcet, A. 1819. On the specific gravity, and temperature, in different parts of the ocean, and in particular seas with some account of their saline contents. Philosphical Transactions Royal Society of London 109 161-208. 

The concept of salinity was introduced by Georg Forchhammer in 1865. From extensive analyses of seawater samples, he was able to demonstrate the validity of Marcet s principle for the most abundant of the salt ions chloride, sodium, calcium, potassium, magnesium, and sulfete. Thus, he recognized that the salinity of seawater could be inferred from the easily measurable chloride concentration or chlorinity. The details of this relationship were worked out by Martin Knudsen, Carl Forch, and S. E L. Sorenson between 1899 and 1902. With the international acceptance of their equation relating salinity to chlorinity (S%o = 1.805 Cl%o + 0.030), the standardization necessary for hydro-graphic research was provided. A slight revision in this equation (S%o = 1.80655 Cl%o) was made in 1962 by international agreement. 

This constancy in relative ion concentration was first postulated by Alexander Marcet in 1819 and, hence, is known as Marcet s Principle or the Rule of Constant Proportions. Formally stated, it says that regardless of how the salinity may vary from place to place, the ratios between the amounts of the major ions in the waters of the open ocean are nearly constant. ... 

On February 6th of the following year Berzelius wrote again to Dr. Marcet, telling him that they had been mistaken about the tellurium (8) ... 

His students and friends adored him. Although Friedrich Wohler spent only a few months in Stockholm, his contact with the great master influenced the whole course of his life. Their frequent exchange of intimate letters lasted many years, to be interrupted at last only by the death of Berzelius. Berzelius correspondence with Dr. Alexandre Marcet, Sir Humphry Davy, Dr. W. H. Wollaston, and others was also extensive. 

Hatchett was one of the educated men, with the sagacity for which this nation is famous who helped to entertain Berzelius in 1812 (29). Since Berzelius understood little of what the English chemists were saying, he had a dull time at Hatchett s dinner party. It was there nevertheless, that he first made the acquaintance of Dr. Alexandre Marcet. 

When the English translation of Berzelius treatise on the composition of animal fluids appeared, Dr. Marcet wrote, Your great memoir is an honour to us. Hatchett, however, complains that, when you hunted in his grounds, you didn t even cite him but I have explained to him, as best I could, the haste in which you found yourself and your necessity of abstaining from reference work. ... 

I am very sorry, replied Berzelius, .. . . but if you take this matter up with him again, tell him that I am absolutely ignorant of any work of his on these subjects other than that of the testaceae.. . . Berzelius also explained that he had confined himself almost entirely to a description of his own work. Dr. Marcet replied, I gave your little compliment to Hatchett, who seemed entirely satisfied with it, and sends you his best regards. You will see on consulting Thomson [Thomas Thomson, A... 

On April 22, 1813, Berzelius wrote from Stockholm to Dr. Alexandre Marcet of London ... 

The letters of Dr. Alexandre Marcet to Berzelius give us a pleasing picture of Dr. Wollaston s friendly nature. On May 24, 1814, Dr. Marcet wrote ... 

On another occasion Dr. Marcet wrote, The excellent Wollaston has just lost his father, who leaves a large fortune, which I dare to reply, will not spoil our friend (12). On January 23,1816, he suggested in reply to a question asked by Berzelius,... 

In May, 1813, Dr. Marcet wrote to Berzelius, Our friend Tennant has just been elected professor of chemistry at Cambridge after a very long struggle with a candidate who had many friends. His position demands that he give twenty lectures a year, which will not be very difficult for him (22). Berzelius replied, Congratulate Tennant for me on his new profession and tell him that we expect from his hands the life of Newton more correct than we have yet seen it (23). 

Tennant was destined to give his lecture course at Cambridge only once, for his life was cut short by a tragic accident, the following account of which was written by Dr. Marcet to Berzelius on March 29,1815 ... 

In Lyons, Arfwedson and Berzelius observed the manufacture of silk and velvet in the homes of the workers. In Geneva they visited Dr. and Mrs. Alexandre Marcet. While they were in Zurich, Professor M. A. Pictet of Geneva announced to them that they had both been elected to honorary membership in the Helvetian Scientific Society. 

On one of Berzelius busy summer vacations at the hospitable home of Assessor J. G. Gahn, they discovered still another cerium mineral. For two and a half months, said Berzelius m a letter to Dr. A. Marcet on October 7, 1814, we occupied oui selves with nothing whatever except... 

Dr. Alexandre Marcet stated that Smithson Tennant discovered the presence of iodine in sea water just before his fatal accident in 1815 (128). In his famous research on the composition of sea water, J. G. Forchhammer stated that iodine was the first element in sea water dis-... 

According to the analysis of Marcet, the water of the Dead Sea contains 24-6 per cent, of fixed matter, and possesses an extraordinary density, 1-211—... 

The concept of constancy of the chemical composition of sea water, i.e., that the ratios of the major dissolved constituents of sea water do not vary geographically or vertically in the oceans except in regions of runoff from the land or in semienclosed basins, was firsr proposed indirectly in 1819 by Marcet and expanded later by Forchammer and Dittmar. The concept... 

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