American Journal of Science and Arts最新文献_第4页

On the coincidence of the bright lines of the oxygen spectrum with bright lines in the solar spectrum 氧光谱的亮线与太阳光谱的亮线重合

American Journal of Science and Arts Pub Date : 1879-06-13 DOI: 10.2475/ajs.s3-18.106.262

H. Draper

引用次数: 3

Notice of recent scientific publications in Brazil; O. A. Derby on the geology of the lower Amazonas 巴西近期科学出版物公告;O. A. Derby对亚马逊河下游地质的研究

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.464

R. Rathbun

引用次数: 0

First catalogue of radiant points of meteors 第一份流星辐射点目录

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/AJS.S3-17.102.468

F. Sawyer

引用次数: 0

On the dark lines of oxygen in the solar spectrum on the less refrangible side of G 在太阳光谱中氧的暗线上在G的不易制冷的那一边

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.448

J. Draper

引用次数: 0

On a new absolute galvanometer 在一个新的绝对振镜上

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.475

N. Hodges

{"title":"On a new absolute galvanometer","authors":"N. Hodges","doi":"10.2475/ajs.s3-17.102.475","DOIUrl":"https://doi.org/10.2475/ajs.s3-17.102.475","url":null,"abstract":"IN the ordinary form of galvanometer the current is measured by the ratio of the force it exerts on the needle to the directive force of the earth, the ratio being determined by a measurement of the angle of deflection. The moment of the force with which a unit current acts on the needle may be expressed in a series of the form G1 gl sin IJ + G,g, sin IJ Q,'(IJ) + etc. where G\" G 2 are constants depending on the dimensions of the coil, and g\" g 2 on those of the suspended apparatus, coil or magnet, as the case may be. Q/ ({}), Q/ ({}) are quantities varying with the deflection. Only in case all the terms after the first may be neglected are the values of the current proportional to the tangents of the deflections. With a single coil this is not the case. By increasing the number of coils and suitabl,V placing them, the magnetic field may be rendered more uniform. In reading the deflection ei ther a di vicled circle or a telescope and scale may be used. With the divided circle the deflection may be as great as 45°, but not more, or else the instrument would not be sensitive to changes in the current. The use of telescope and scale necessitates much smaller deflections. To regulate the strength of the current shunts of small resistance often have to be used; and the proportion of the current throngh the instrument is rendered doubtful. If, instead of placing the plane of the coils parallel with the magnetic meridian, they are placed perpendicular to it, the sum of the force of the current and of the directive force of the earth would influence the magnet.","PeriodicalId":7651,"journal":{"name":"American Journal of Science and Arts","volume":"1 1","pages":"475 - 476"},"PeriodicalIF":0.0,"publicationDate":"1879-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81158214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Notice of recent additions to the marine fauna of the eastern coast of North America 北美东海岸最近增加的海洋动物群的通知

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.472

A. E. Verrill

引用次数: 32

On ethylidenamine silver sulphate 乙二胺硫酸银

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.427

W. Mixter

{"title":"On ethylidenamine silver sulphate","authors":"W. Mixter","doi":"10.2475/ajs.s3-17.102.427","DOIUrl":"https://doi.org/10.2475/ajs.s3-17.102.427","url":null,"abstract":"ALDEHYDE AMMONIA precipitates metallic silver from many of its salts almost as readily as from the nitrate. A mixture of solutions of silvet' sulphate and aldehyde ammonia produces a mirror when warmed, and at common temperatures evaporates to dryness, with but slight decomposition. The fact that a sulphate solution decomposed less readily than the nitrate led to the hope that an investigation of the sulphate compound would throw more light on the constitution of silver amines. The first experiments were made with ammoniacal aqueous solutior.s of silver sulphate and aldehyde ammonia. Analyses proved the crystalline product to be a mixture. Alcoholic ammonia was next used as a solvent, and the analysis of the first crop of crystals showed nearly pure Ag2S04(NH~)4' 0'6 per cent of carbon was found and a solution of the crystals reacted for aldehyde. Aqueous solutions of silver sulphate and a lal'ge excess of aldehyde ammonia, over four molecules of the latter to olle of the former, yielded either mixtures or ammonio silver sulphate. When, however, aldehyde ammonia is dissolved in a small quantity of water, and silver sulphate, in the proportion of one molecule of the lat.ter to four molecules of the formel', is slowly added with constant agitation; and after some hours the small black residue filtered off and the solution left to spontaneous evaporation, few or no crystals of the ammonio, sulphate form, but colo1'less tl'ansparent crystals separate, whICh react strongly for aldehyde. At summer temperatures tabulat' crystals, and at from 10° to 15° C. elongated crystals, predominate. The following analyses were made of carefully selected and well-defined tabular crystals, which were from 2 to 5mm in diameter, and which were freed as much as possible from the mother liquor by blotting paper, then washed with alcohol and finally with ether. They were considel'ed dry when they did not lose weight on the balance in five or ten minutes.","PeriodicalId":7651,"journal":{"name":"American Journal of Science and Arts","volume":"26 1","pages":"427 - 429"},"PeriodicalIF":0.0,"publicationDate":"1879-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80271141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the force of effective molecular action 有效分子作用的力

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.433

W. A. Norton

引用次数: 0

The forests of central Nevada, with some remarks on the those of adjacent regions 内华达中部的森林，并对邻近地区的森林作一些评论

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/ajs.s3-17.102.417

C. Sargent

{"title":"The forests of central Nevada, with some remarks on the those of adjacent regions","authors":"C. Sargent","doi":"10.2475/ajs.s3-17.102.417","DOIUrl":"https://doi.org/10.2475/ajs.s3-17.102.417","url":null,"abstract":"To the traveler crossing the Great Basin by the line of the Pacific Railroad the country will appear almost as destitute of trees as the great plateau over which he has passed in approaching the Rocky Mountains from the east. This first impression will disappear, however, should he penetrate farther south, and ascend some of the low mountain ranges, which, with a general north-and-south trend, everywhere cut up this elevated interior region into long, narrow valleys. As compared with our Atlantic forests, or those still nobler ones which, farther to the west, owe their existence to the influence of the Pacific, the forests which clothe, with a scanty and stunted vegetation, the mountain slopes of Nevada are miserably poor in extent, productiveness, and especially in the number of species of which they are composed. Actually they are of immense value. For scanty as they are, they regulate and protect the rare and uncertain streams on which the agl'lculture of Nevada depends, and furnish a large population with fuel and lumber; a population, too, which, while consuming and wasting enormously its forests in vast mining operations, is practically cut off, by its isolation and the cost of transportation, from outside supply. A hurried journey made in Septemper last, undertaken for the purpose of studying in situ the trees of the\" Great Basin,\" and of introducing into cultivation some of the peculiar plants of that region, took me to the great mining center of Eureka, and then throllgh Dry and Fish-spring valleys seventy-five , miles further southwest into the Monitor Range, to the point","PeriodicalId":7651,"journal":{"name":"American Journal of Science and Arts","volume":"186 1","pages":"417 - 426"},"PeriodicalIF":0.0,"publicationDate":"1879-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78887174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Notes on the satellites of Saturn 关于土星卫星的说明

American Journal of Science and Arts Pub Date : 1879-06-01 DOI: 10.2475/AJS.S3-17.102.430

M. Mitchell

{"title":"Notes on the satellites of Saturn","authors":"M. Mitchell","doi":"10.2475/AJS.S3-17.102.430","DOIUrl":"https://doi.org/10.2475/AJS.S3-17.102.430","url":null,"abstract":"THE object glass of the telescope used in the observations which follow is of twelve and one-third inches diameter. Its deo ni tion is good. The telescope is used in such observations as its very imperfect mechanism will allow; the;;e are observations of the conjunctions of the satellites with the edge of Saturn's ring, of size and color, and of differences of right ascension. The last are made b.y connecting with the chronograph, and recording the time of passage of the satellites over a fixed wire. In the course of these observations such different relati ve magnitudes have been given to the small satellites, on different evenings, as to lead to the suspicion that some of them are variable. 'rhe sparkle of Tethys and the grayish blue color of Hhea make it seem unlikely that sUlall stars can have been taken for these two satellites; 'in the case of Encelad us and Dione m istakes are more easily made; but the rapid motion of Enceladus soon establishes its identity. The most noticeable changes are in Rhea. In 1877, Hhea is recorded as small on Nov. 30th; as dull on Dec. 3d; as blurry and large, Dee. 14th; and as ruddy, Dec. 18th. In 1878 Rhea is recorded as faint Oct. 3d and Oct. 16th; as bright on Oct. 25th, and on Dec. 3d it is called nearly as bright as 'ritan.","PeriodicalId":7651,"journal":{"name":"American Journal of Science and Arts","volume":"11 1","pages":"430 - 432"},"PeriodicalIF":0.0,"publicationDate":"1879-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87446411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2