Augtist 30, 1877] 



NATURE 



367 



Gramme's patent, made in Paris, and is a double light 

 machine, that is, it has two sets of brushes, and is wound 

 with wire of such a size as to give a current of sufficient 

 intensity for my purposes. It is nominally a 350 candle- 

 light machine, but the current varies in proportion to the 

 rate of rotation, and I have also modified it by chani;inL; 

 the interior connections. The machine can produce as a 

 maximum a light equal to 500 standard candles, or by 

 slowing the rotation of the bobbin the current may be 

 made as feeble as that of the weakest battery. In prac- 

 tical use it is sometimes doing the work of more than 

 fifty large Grove nitric acid cells, and sometimes the 

 work of a single Smee. 



The Gramme machine could not be used to work an 

 induction coil when it first reached me, because when the 

 whole current was sent through the Foucault interrupter 

 of the Ruhmkorff coil, making r,oco breaks per minute, 

 the electro-magnets of the Gramme did not become suf- 

 ficiently magnetised to give an appreciable current. But 

 by dividing the current so that one pair of the metallic 

 brushes, which collect from the revolving bobbin, sup- 

 plied the electro-magnets, the other pair could be used 

 for exterior work, no matter whether interrupted or con- 

 stant. The current obtained in this way from one pair 

 of brushes when the Gramme bobbin is making 1,200 

 revolutions per minute is equal to 100 candles, and is 

 greater in quantity and intensity than one would like to 

 send through a valuable induction coil. I usually lun 

 the bobbin at 622 revolutions per minute, and this rate will 

 readily give 1,000 10- inch sparks per minute with the iS- 

 inch coil. Of course a Pliicker's tube lights up very vividly 

 and generally ; in order to get the maximum effect I 

 arrange the current so that the aluminium terminals are 

 on the point of melting. The glass, particularly in the 

 capillary part, often gets so hot as to char paper. The 

 general appearance of the machine is shown in Fig. i. 



As long as the Gramme bobbin is driven at a steady 

 rate the current seems to be perfectly constant, but varia- 

 tions of speed make marked differences in the current, 

 and this is especially to be avoided when one is so near 

 the limit of endurance of Pliicker's tubes. A reliable 

 and constant motor is therefore of prime importance for 

 these purposes. A difference of one per cent, in the 

 speed in the engine sometimes cannot be tolerated, and 

 yet at another time one must have the power of increas- 

 ing and diminishing the rate through wide limits. The 

 only motor, among many I have examined and tried, 

 that is perfectly satisfactory, is Brayton's Petroleum 

 Ready INIotor. 



This remarkable and admirable engine acts like an 

 instrument of precision. It can be started with a match, 

 and comes to its regular speed in less than a minute ; it 

 preserves its rate entirely unchanged for hours together. 

 Moreover, it is economical, cleanly, and not more noisy 

 than a steam engine. The one of two-horse power I 

 have, ran for six mouths, day and night, supplying water 

 and air to the aquaria in the Centennial Exhibition at 

 Philadelphia. At any time on going into the laboratory 

 it can be started in a few seconds, even though it has 

 not been running for days. 



Henry Draper's Observatory, Hastings-on-Hudson, 

 New York 



THE NATURAL HISTORY OF THE JENISSEI 



A N account of the Swedish Overland Expedition 

 -'"*- to the Jenissei in the summer of 1S76, the 

 cost of which was defrayed by Mr. Oscar Dickson 

 of Gothenburg-, has appeared in the Giitcborgs Haiuiels 

 Tidnino. The expedition was under the leadership of 

 Dr. Hjalmar Theel of Upsala, who was accompanied by 

 Botany- Docent W. Arnell, Philosophy-Candidate F. 

 Tryboin, Zoologist, and Rector M. Brenner, Botanist, from 



Finland. Docent Sahlberg, Entomologist, from Helsing- 

 fors, also went with the expedition to the Jenissei with 

 the intention of prosecuting independent researches there. 

 The party travelled by Nischni-Novgorod, Perm,Tjumen, 

 Tomsk, and Krasnojarsk on the Jenissei, arriving at the 

 last place on June S. 



We regret that our space permits of our giving only the 

 following account of the natural history of the Jenissei by 

 Dr. Thc=el :— 



The Jenissei has a length of about 1,660 English miles 

 below Krasnojarsk. The banks are sometirres pretty 

 high and bold, sometimes low, alternating in this respect 

 with each other, so that, when the left is high, the right is 

 the opposite. Where the bank is low and exposed to 

 inundations, willows thrive beyond everything. The high 

 banks are clothed with Piiius ohovala and cciiibra, and 

 larch. At Jeniseisk the river is about \h versts broad, 

 f;iadually widening northward, till at Kurejka it is five 

 versts broad. Between Tolstoros and Goltschika the 

 river widens and assumes the appearance of a lake more 

 than sixty versts wide. Here the tides are quite observ- 

 able. At Dudinskoj a depth reaching twelve fathoms was 

 found. 



The Russian population of the Jenissei Valley is very 

 sparse and uncivilised, and inferior, as far as the fine arts 

 are concerned, to some of the Asiatic races. Cattle rearing 

 is in its infancy, though there are perhaps few regions 

 more suited for it than the valley of the Jenissei. Cows 

 are met with as far as Dudinskoj, but their proper 

 management did not appear to be understood. At 

 villages on the upper Jenissei, with as many as forty or 

 fifty cows, a glass of milk could scarcely be obtained. The 

 making of cheese is completely unknown, the making of 

 butter nearly so. There are horses as far north as 

 Dudinskoj, sheep only to Vorogova, and no goats north 

 of Jeni;eisk. Cultivation is at a still lower standpoint, rye 

 not being at present grown below Antsiferova, sixty- 

 seven versts north of Jeniseisk, and oats toZotina, 60" 55' 

 N. lat. Potatoes are grown to Turuchausk, but are there 

 very small. For some years Skoptzi settleel on the 

 Chantajka river, 68° 20' N. lat., have successfully grown 

 potatoes. 



Fish forms the principal food of the people, and during 

 summer nearlyevery one is a fisher. Fishing is carried 

 on with various kinds of nets, with lines and hooks, and 

 even with leister and torch. There are found in the 

 Jenissei pike, ruffe, perch, burbot, Cypriiius ciirassius, 

 terch, Thymalliis I'uloaris, several species of the family 

 Lciicisciis, among them one which strongly resembles our 

 common roach, a kind o{ Petromyzon, Gasterostcus pun- 

 i^iliiis, a kind of bullhead {Co/Ziis), &c. All these are of 

 inferior importance for domestic use, and mostly serve as 

 food for dogs. The more valuable are the sturgeon, 

 salmon, and coregonus. There ar'e two varieties of 

 sturgeon, the commo.i sturgeon or " Ossetrina," Accipilcr 

 s/iuiii, and the sterlet, Ac. ntlhcnus. The Ossi/n'na is 

 caught along the whole Jenissei, and sometimes reaches a 

 weight of 225 lbs. The sterlet is not found north of 

 Dudinskoj, and commonly weighs 3 or 4 lbs., but some- 

 times reaches iS lbs. There is another called the prickly 

 sturgeon, " Kosterska," believed to be the young of the 

 Osscirina. There are many varieties and transition forms 

 of sturgeon, rendering their proper classificaticn difficult. 

 The salmon is most numerous in the upper course of the 

 liver at Minousinsk, where a profitable fishery is car- 

 ried on. Two types are distinguished, " Tajmen " and 

 '' Kunschja." The former is caught in greatest numbers 

 iu the upper course of the river, and weighs 40 to 60 lbs. ; 

 the latter is found in lakes on the tundra, and very seldom 

 in the Jenissei below Dudinskoj. At the Nichandrovska 

 Islands a salmon, probably a Tajmen, was caught, which 

 was nearly five feet long and weighed between 80 and 

 100 lbs. Of the Coregonus the following species were 

 found in the Jenissei ; — Njelma (C leiicichthys), Tschir 



