POPULAR SCIENCE MONTHLY.
count of subsequent observations made with dead hazel branches (pea sticks), which had been found to develop considerable suction force, amounting in one case to nineteen inches and a half of mercury with a stick eighteen inches long. He concluded by expressing the opinion that in recent attempts to explain the mechanism of the transpiration current, the part played by the "imbibition" of the cell walls had been underestimated, and urged that what is especially requisite for a further advance is a more complete investigation of the properties of a dead stick.
Chinese Cheap Money.—The Chinese, as all the world may know, have cheap money, their standard of value being a copper coin about the size of a quarter of a dollar, with a square hole in the middle by which it may be strung, which is commonly called cash—in Chinese, tsien. They are strung by hundreds, with a knot to mark each hundred, and when large sums are to be used, strings enough to make out the amount are hung upon the shoulders of the carrier. Mr. Carles, a traveler in Korea, relates that he had to hire a special pony on one of his excursions to carry his cash, and that at one time he met two ponies carrying twenty-four thousand cash, or thirty dollars, to pay the workmen at a certain mine. The Chinese money-tellers become very expert in counting these cash and detecting false ones, for even these copper pieces, representing as little value as money can be made to do, are falsified. Emblems manufactured out of iron or of sand and gluten are often put upon the strings in place of the real bronze coin; in fact, a certain number of these spurious pieces are nearly always found. They are detected and separated from the genuine by boiling the pile or string. The sand and gluten cash are dissolved, and the iron are exposed. The accountant weighs what is left; or, if the sum represents millions, he boils a few thousand and makes an average from the result which he applies to the whole.
The Smoke Nuisance.—A recent English inquiry into the smoke nuisance and the possibility of its abatement is noticed in Industries and Iron. The commission's report contains much interesting information, and sums up as follows: In presenting their report the committee express their conviction that in the great majority of cases the black smoke thrown into the air during the combustion of coal is preventable, either by hand or mechanical firing, and without great cost to the consumer. Often the prevention of smoke is accompanied with saving of expense, in that an increase of heat is developed by a more perfect combustion of the fuel; and where live fire bars are adopted—that is, where the bars have an automatic reciprocating motion—an inferior and cheaper quality of coal can be used, and thus a further saving of expense effected. The consumption of fuel was found to be lower in boilers fired by machine than in those fired by hand. In short, they say a manufacturing district may be free from manufacturing smoke—at least from the steam boilers, with which alone the committee have concerned themselves—and they give ample information as to the means by which it may be so freed. As the discharge of black smoke from factory chimneys was made a criminal offense in England by the Public Health Act of 1875, all that is necessary now to abate the nuisance is a call by public opinion for the application of the law.
The Earliest Animal Life.—The president of the Geological Section of the British Association, J. E. Marr, opened his presidential address, on stratigraphical geology, with a reference to the points in geological history of which we are ignorant. Specially prominent among these is that of the animal life of the earth during the vast length of time previous to the Cambrian period. The extraordinary complexity of the earliest known Cambrian fauna has long been a matter of surprise, and the recent discoveries in connection with the Olenellus fauna do not diminish the feeling. We may look forwardwith confidence to the discovery of many faunas older than those of which we now possess certain knowledge, but until these are discovered the paleontological record must be acknowledged to be in a remarkably incomplete condition. Valuable work has recently been done in proving the existence of important groups of stratified rocks deposited previously to the beds containing the earliest known Cambrian fossils. With our