SCIENTIFIC SUMMARY. 
91 
fragments of marble and powdered marble, first pouring distilled water 
through, till it passes perfectly limpid. — Journal fur praktische Chemie. 
Organic Matter in Water. — As it has been proposed to obtain the future 
water-supply of London from the English lakes, it is of interest to compare 
(as has been done by the Chemical News ) the analysis of the water of the 
lakes with that of the London waterworks. According to Mr. Way, the 
grains of organic matter per gallon is in — 
River Lowther 062 
Haweswater 062 
Ulleswater ....... 0-35 
Thirlmere . . , . , . . 077 
giving an average of 0*59 grains. 
According to Dr. Letheby, the organic matter per gallon is in the — 
Grand Junction Waterworks .... 0-60 
West Middlesex 0-48 
Southwark and Yauxhall .... 064 
Chelsea 0-56 
Kent 0*03 
New River 0-22 
East London . 0-56 
showing an average of 044 grains ; or a balance against Cumberland of 
015 grains of organic matter per gallon. — Vide Chemical News, November. 
A Crystalline Fatty Matter in Urine. — At a recent meeting of the Royal 
Society, Mr. Edward Schunck read a paper with the above title. Mr. 
Schunck says that the occurrence of fatty matter in urine is a somewhat 
rare phenomenon, and is generally considered as a symptom of disease. 
In most of the instances that have come under his notice, it was found 
associated with albumen in which the fatty particles were embedded ; more 
frequently, however, it is found enclosed in cells so heavy as to sink to the 
bottom of the vessel. Mr. Schunck gives the following method for the 
extraction of the peculiar brown-yellow oil which he described. Healthy 
urine is filtered through animal charcoal, till the percolating liquid ceases to 
be decolorised, and begins to pass with extreme slowness. It will be 
found that a very small quantity of charcoal will decolorise a very large 
portion of the liquid. The charcoal is then well washed with water to dis- 
solve the soluble salts, dried, and afterwards treated with boiling alcohol, to 
which it communicates a bright-yellow colour. The liquid must then be 
filtered, evaporated, and the brown syrup residue mixed with water, 'which 
deposits a brown semifluid fatty matter, which can be separated by filtra- 
tion. 
On Blue Litmus Paper as a Test for Acidity. — In the course of a recent 
discussion at the French Academy, on the subject of silkworm disease, 
M. Chevreul made some interesting observations on the above subject. It 
appears that the most delicate blue paper owes its colour to the red prin- 
ciple of litmus united with subcarbonate of potash ; and when a body 
reddens this, it only signifies that the substance has more affinity for potash 
than the red colouring matter of litmus has. But in the preparation of 
ordinary blue litmus paper, instead of using paper free from mineral matter, 
