This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1810 Excerpt: ...of inflammable air, de-of b.die- termining it to be at least seven times lighter than rising in the common air. Soon after which, it occurred to Dr13' Black, that perhaps a thin bag filled with inflammable jjiack air might be buoyed up by the common atmosphere; MrCavailo. and he thought of having the allantoisof a calf prepared for this purpose: but his other avocations prevented him from prolecuting the experiment. The fame thought occurred some years afterwards to Mr Cavallo; and he has the honour of being the first who made experiments on the subject. He lirfl tried bladders; but the thinnest of these, however well scraped and prepared, were found too heavy. He then tried Chinese paper; but that proved so permeable, that the vapour passed through it like water through a sieve. His experiments, therefore, made in the year 1782, proceed1 ed As..station discovered by Mons. Montgolfier. ed no fnrthrr tbitiu blowing up soap-bubbles with in-flammable air, which ascended rapidly to the ceiling, 7 and broke against it. But while the discovery os the art of aerostation seemed thus on the point of being made in Britain, it was all at once announced in France, and that from a quarter whrrce nothing of the kind was to have been and finely decorated, expected. Two brothers, Stephen and John Mont-golfier, natives of Annonay, and mailers of a consider-able pEp.T-manuf.'.ctory there, had turned their thoughts towards this project as early as the middle of the year 1782. The idea was iiril suggested by the natural ascent of the smoke and clouds in the atmosphere; and their design was to form an artificial cloud, by inclosing the smoke in a bag, and making it carry up the cover-ing al ng with it-.Towards the middle of Novt-mber 8 that year, the experiment was made at...

Excerpt: ...amidst a crowd of honest people seeking recreation after a long day's work, groups of older girls walking and talking gaily with young men of their acquaintance, and happy children holding their parents' hands. This cruel exploitation of the childish eagerness for pleasure is, of course, possible only among a certain type of forlorn city children who are totally without standards and into whose colorless lives a visit to the amusement park brings the acme of delirious excitement. It is possible that these children are the inevitable product of city life; in Paris, little girls at local fetes wishing to ride on the hobby horse frequently buy the privilege at a fearful price from the man directing the machinery, and a physician connected with the New York Society for the Prevention of Cruelty to Children writes: "It is horribly pathetic to learn how far a nickel or a quarter will go towards purchasing the virtue of these children." The home environment of such children has been similar to that of many others who come to grief through the five-cent theatres. These eager little people, to whom life has offered few pleasures, crowd around the door hoping to be taken in by some kind soul and, when they have been disappointed over and over again and the last performance is about to begin, a little girl may be induced unthinkingly to barter her chastity for an entrance fee. Many children are also found who have been decoyed into their first wrong-doing through the temptation of the saloon, in spite of the fact that one of the earliest regulations in American cities for the protection of children was the prohibition of the sale of liquor to minors. That children may be easily demoralized by the influence of a disorderly saloon was demonstrated recently in Chicago; one of these saloons was so situated that the pupils of a public school were obliged to pass it and from the windows of the schoolhouse itself could see much of what...

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ...the number of replications, if no check plots were used. As doubling the number of replications will in general give a standard deviation about equal to the original standard deviation divided by the square root of 2, it will reduce variability about 30 %---7071. If alternat ing with check plots will consistently reduce variability more than 30 per cent it will be generally a more economical way to control error. Similarly, the use of check plots in every third plot requires as much land as would be required by increasing the number of replications by 50 per cent (using three replications instead of two, or fifteen instead of ten). From this relation the reduction of variability necessary if this practice is to equal replication in effectiveness can be easily computed. Such determinations for check plots at various intervals are shown in Table 30. Table 30.--Reduction Of Variability By The Use Of Check Plots Equivalent To That Probably Attainable With The Same Number Of Plots By Replication. Reduction in standard deviation to If protected single-row or 3-row plots are used in preliminary experiments a more reliable measure of soil productivity is available, and consequently the adjustment of yields is more likely to be of value, than when unprotected single-row plots are used. By the use of planting plans of the sort employed in these experiments, it is possible to adjust the yields by a somewhat shortened method. If adjustment of yield is effective in reducing plot variability in this sort of test it can be accomplished with but little increase in labor. In each of the tests reported in this paper a trial of the effectiveness of adjusting yields by means of check plots was made, the criterion of accuracy being in each case the variability of the yields of ...